Multiple Function Dual Core Flooding Apparatus and Methods

ABSTRACT

A dual core flooding apparatus is disclosed. The dual core flooding apparatus includes at least two core holders each configured to contain a core plug. The dual core flooding apparatus includes a fluids delivery system configured to inject one or more fluids into the core holders and core plugs. The dual core flooding apparatus includes an image capture system, a density and viscosity measurement system, and at least two oil/water separators. The dual core flooding apparatus also includes at least two back pressure regulators configured to maintain a pore pressure in the core plugs and an automated confining pressure system configured to maintain a confining pressure in each core holder. The dual core flooding apparatus further includes a data acquisition system, differential pressure measurement systems, and effluent measurement systems.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority from U.S.Non-provisional application Ser. No. 15/452,949 filed Mar. 8, 2017, andtitled “MULTIPLE FUNCTION DUAL CORE FLOODING APPARATUS AND METHODS,”which claims priority from U.S. Provisional Application No. 62/372,489filed Aug. 9, 2016, and titled “MULTIPLE FUNCTION DUAL CORE FLOODINGAPPARATUS AND METHODS,” each of which are incorporated by reference intheir entirety for purposes of United States patent practice.

BACKGROUND Field of the Disclosure

Embodiments of the disclosure generally relate to apparatus and methodsfor the evaluation of flow characteristics and behaviors of fluids, suchas crude oil, seawater, supercritical CO₂/gas CO₂, and chemicalsolutions, in rock samples obtained from reservoirs (for example,sandstone or carbonate reservoirs).

Description of the Related Art

During rock coring in development and exploration of a hydrocarbonreservoir to produce hydrocarbons such as oil and gas, rock core samplesof subsurface material are collected. The process of obtaining thesesamples, referred to as “cores,” “core samples,” or “core plugs,”produces a corebore hole that is formed into and defined by andtraverses the subsurface (that is, the rock or other material beneaththe surface). A core plug is the extracted subsurface material (such asrock or stone) obtained from the subsurface through the newly formedcorebore. In some instances, core plugs can be taken from and compose aportion of a reservoir or formation.

Following extraction, core plugs may transported to a laboratory orother location, and analyzed to evaluate characteristics of thehydrocarbon reservoir or subsurface. For example, core analysis mayinclude an analysis of rock properties of the core plug, permeability ofthe core plug, and flooding performance. A typical core analysis systemincludes a single stationary core holder that holds one core plug forperforming tests on the core plug. Such a system may only provide forone orientation of the single stationary core holder and for limitedflooding tests with a single fluid. Additionally, such systems may beunable to accurately reproduce and maintain a range of conditions,including reservoir conditions, for core analysis.

SUMMARY

Analysis of core plugs obtained from a reservoir or formation may beuseful in evaluating properties of the rock formation, the reservoirhydrocarbons, and other aspects. In some instances, it may be desirableto evaluate the performance of secondary oil recovery processes, such aswater flooding, tertiary oil recovery processes, such as gas infectionand chemical flooding, and conformance control by plugging agents inhigh permeable zones. Additionally, it may be desirable to evaluate theperformance of such processes at specific temperature and pressures.

In some embodiments, a dual core flooding apparatus for analyzing aplurality of core plugs is provided. The apparatus includes a first coreholder and a second core holder. Each core holder is operable to containat least one core plug of the plurality of core plugs. Each core holderincludes an inlet port operable to receive at least one fluid into thecore holder and into contact with the core plug and an outlet portoperable for removal of the at least one fluid from the core holder. Theapparatus further includes a fluids delivery system in fluidcommunication with the inlet port. The fluids delivery system isoperable to introduce the at least one fluid into at least one of thefirst core holder and the second core holder through the respectiveinlet port. The apparatus also includes a first separator operable toseparate hydrocarbon fluid from the at least one fluid and in fluidcommunication with the outlet port of the first core holder. Theapparatus also includes a second separator operable to separatehydrocarbon fluid from the at least one fluid and in fluid communicationwith the outlet port of the second core holder. Additionally, theapparatus includes a pressure confining system operable to maintain afirst confining pressure in the first core holder and a second confiningpressure in the second core holder. The apparatus further includes afirst back pressure regulation system operable to maintain pore pressurewithin a core plug contained in the first core holder independent of apore pressure associated with the second core holder. The apparatus alsoincludes a second back pressure regulation system operable to maintainpore pressure within a core plug contained in the second core holderindependent of the pore pressure associated with the first core holder.

In some embodiments, the dual core flooding apparatus includes a densitymeter coupled to the outlet port of the first core holder and the outletport of the second core holder. The density meter is configured tomeasure a density of the at least one aqueous fluid exiting from theoutlet port or the second outlet port. In some embodiments, the dualcore flooding apparatus includes a viscosity meter coupled to the outletport of the first core holder and the outlet port of the second coreholder. The viscosity meter is configured to measure a density of the atleast one aqueous fluid exiting from the outlet port or the secondoutlet port. In some embodiments, the dual core flooding apparatusincludes an image capture apparatus. The image capture apparatus anobservation viewing cell coupled to the fluids delivery system via atleast one valve and a camera configured to capture images of the atleast one fluid before the at least one fluid is received by the firstcore holder. The image capture apparatus may include a pump operable tomaintain a confining pressure in the viewing cell. In some embodiments,the fluids delivery system includes at least one fluid accumulator andat least one pump coupled to the at least one fluid accumulator via atleast one valve. In some embodiments, the fluids delivery systemincludes a plurality of valves arranged to define a first fluid flowpath from a first fluid accumulator to the inlet port of the first coreholder and a second fluid flow path from a second fluid accumulator tothe inlet port of the second core holder when a first group of theplurality of valves are open and a second group of the plurality ofvalves are closed. In some embodiments, the plurality of valves arefurther arranged to define a third fluid flow path from the first fluidaccumulator to the inlet port of the first core holder and a fourthfluid flow path from the first fluid accumulator to the inlet port ofthe second core holder when a third group of the plurality of valves areopen and a fourth group of the plurality of valves are closed. In someembodiments, the dual core flooding apparatus includes a firstdifferential pressure measurement apparatus configured to measuredifferential pressure across the first core holder and provide a firstdifferential pressure measurement to the data acquisition system and asecond differential pressure measurement apparatus configured to measuredifferential pressure across the second core holder and provide a seconddifferential pressure measurement to the data acquisition system. Insome embodiments, the dual core flooding apparatus includes a firsteffluent measurement system coupled to the first back pressureregulation system. The first effluent measurement system includes afraction collector configured to measure an amount of liquid effluentproduced from the first back pressure regulation system. In someembodiments, the dual core flooding apparatus includes a second effluentmeasurement system coupled to the second back pressure regulationsystem. The second effluent measurement system includes a fractioncollector configured to measure an amount of liquid effluent producedfrom the second back pressure regulation system. In some embodiments,the at least one fluid includes live crude oil, dead crude oil, orseawater. In some embodiments, the properties include at least one of adensity, a viscosity, an amount of hydrocarbon fluid, and an amount ofwater. In some embodiments, the data acquisition system is configured toacquire a first differential pressure across the first core holder and asecond differential pressure across the second core holder.

In some embodiments, a method for dual core flooding of a plurality ofcore plugs is provided. The method includes introducing, by a fluidsdelivery system, at least one fluid into a first core holder and asecond core holder. The first core holder is operable to contain a firstcore plug sample and the second core holder is operable to contain asecond core plug. The method further includes separating, by aseparator, hydrocarbon fluid from the at least one fluid. The separatoris in fluid communication with an outlet port of the first core holderor an outlet port of the second core holder. The method also includesmaintaining, by a pressure confining system, a first confining pressurein the first core holder and a second confining pressure in the secondcore holder. Additionally, the method includes maintaining, by a backpressure regulation system a first pore pressure within the first coreplug sample independent of the pore pressure associated with the secondcore plug. The method further includes acquiring, by a data acquisitionsystem, properties of the at least one fluid exiting from the outletport of the first core holder or the outlet port of the second coreholder.

In some embodiments, the at least one fluid includes a first fluid and asecond fluid different than the first fluid, such that introducing, bythe fluids delivery system, at least one fluid into a first core holderand a second core holder includes introducing the first fluid into thefirst core holder and introducing the second fluid into the second coreholder. In some embodiments, the fluids delivery system includes aplurality of valves and introducing the first fluid into the first coreholder includes opening a first group of the plurality of valves andclosing a second group of the plurality of valves to define a firstfluid flow path from a first fluid accumulator of the fluids deliverysystem to the inlet port of the first core holder and a second fluidpath from a second fluid accumulator of the fluids delivery system tothe inlet port of the second core holder. In some embodiments, the atleast one fluid includes a third fluid, such that introducing, by thefluids delivery system, at least one fluid into a first core holder anda second core holder includes introducing the third fluid into the firstcore holder after introducing the first fluid into the first coreholder. In some embodiments, the at least one fluid includes a singlefluid, such that introducing, by a fluids delivery system, at least onefluid into a first core holder and a second core holder includesintroducing the single fluid into the first core holder and introducingthe single fluid into the second core holder. In some embodiments, thefluids delivery system includes a plurality of valves, such thatintroducing the single fluid into the first core holder and the secondcore holder includes opening a first group of the plurality of valvesand closing a second group of the plurality of valves to define a firstfluid flow path from a first fluid accumulator of the fluids deliverysystem to the inlet port of the first core holder and a second fluidpath from the first fluid accumulator of the fluids delivery system tothe inlet port of the second core holder. In some embodiments, themethod includes introducing, via the fluids delivery system, a foam sluginto the first core holder. In some embodiments, the at least one fluidincludes live crude oil, dead crude oil, seawater or carbon dioxide. Insome embodiments, the properties include at least one of a density, aviscosity, an amount of hydrocarbon fluid, and an amount of water.

In some embodiments, a dual core flooding apparatus for analyzing aplurality of core plugs is provided. The dual core flooding apparatusincludes a first core holder containing a first core plug, a second coreholder containing a second core plug, and a fluids delivery systemconfigured to inject a first fluid into the first core plug and a secondfluid into the second core plug. The dual core flooding apparatus alsoincludes a first back pressure regulation system in fluid communicationwith the first core holder and configured to maintain a first porepressure of the first core plug, and a second back pressure regulationsystem in fluid communication with the second core holder and configuredto maintain a second pore pressure of the second core plug, such thatthe second pore pressure is maintained independently of the first porepressure. The dual core flooding apparatus also includes a pressureconfining system in fluid communication with the first core holder andthe second core holder and configured to maintain a first confiningpressure in the first core holder and a second confining pressure in thesecond core holder.

In some embodiments, the dual core flooding apparatus includes a dataacquisition system configured to obtain properties of the first fluidafter the first fluid exits the first core holder. In some embodiments,the dual core flooding apparatus includes the properties include atleast one of a density, a viscosity, an amount of hydrocarbon fluid, andan amount of water. In some embodiments, the data acquisition system isfurther configured to obtain properties of the second fluid after thesecond fluid exits the second core holder. In some embodiments, thefirst fluid includes live crude oil, dead crude oil, seawater or carbondioxide and the second fluid includes live crude oil, dead crude oil,seawater or carbon dioxide. In some embodiments, the dual core floodingapparatus includes an image capture system positioned between the fluidsdelivery system and the first core holder. The image capture systemincludes a camera configured to capture images of the first fluid beforeinjection into the first core holder

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a dual core flooding apparatus inaccordance with an embodiment of the disclosure;

FIGS. 2A-2D are schematic diagrams of a fluids delivery system of thedual core flooding apparatus of FIG. 1 in accordance with an embodimentof the disclosure;

FIG. 3 is a schematic diagram of the image capture system of the dualcore flooding apparatus in FIG. 1 in accordance with an exampleembodiment of the disclosure;

FIGS. 4A-4D are schematic diagrams of a first core holder and secondcore holder of the dual core flooding apparatus of FIG. 1 in accordancewith an embodiment of the disclosure;

FIGS. 4E-4M are schematic diagrams of orientations of the first coreholder and second core holder in accordance with example embodiments ofthe disclosure;

FIG. 5 is a schematic diagram of a first differential pressuremeasurement system of the dual core flooding apparatus of FIG. 1 inaccordance with an embodiment of the disclosure;

FIG. 6 is a schematic diagram of a second differential pressuremeasurement system of the dual core flooding apparatus of FIG. 1 inaccordance with an embodiment of the disclosure;

FIG. 7 is a schematic diagram of the density and viscosity measurementsystem of the dual core flooding apparatus of FIG. 1 in accordance withan embodiment of the disclosure;

FIG. 8 is a schematic diagram of a first oil/water separation system ofthe dual core flooding apparatus of FIG. 1 in accordance with anembodiment of the disclosure;

FIG. 9 is a schematic diagram of a second oil/water separation system ofthe dual core flooding apparatus of FIG. 1 in accordance with anembodiment of the disclosure;

FIG. 10 is a schematic diagram of a first back pressure regulationsystem and a second back pressure regulation system of the dual coreflooding apparatus of FIG. 1 in accordance with an embodiment of thedisclosure;

FIG. 11 is a schematic diagram of an automated confining pressure systemof the dual core flooding apparatus of FIG. 1 in accordance with anembodiment of the disclosure;

FIG. 12 is a schematic diagram of a first effluent measurement system ofthe dual core flooding apparatus of FIG. 1 in accordance with anembodiment of the disclosure;

FIG. 13 is a schematic diagram of a second effluent measurement systemof the dual core flooding apparatus of FIG. 1 in accordance with anembodiment of the disclosure; and

FIG. 14 is a schematic diagram of a bypass of an image capture systemand a first core holder of the dual core flooding apparatus of FIG. 1 inaccordance with an embodiment of the disclosure; and

FIG. 15 is a block diagram of a data acquisition and control system ofthe dual core flooding apparatus of FIG. 1 in accordance with anembodiment of the disclosure.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with referenceto the accompanying drawings, which illustrate embodiments of thedisclosure. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the illustratedembodiments set forth in the disclosure. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the disclosure to those skilled in the art.

Embodiments of the disclosure include a dual core flooding apparatushaving at least two core holders to enable the simulation of coreflooding and physical displacement processes in oil and gas reservoirsat specific reservoir conditions (for example, temperature andpressure). The dual core flooding apparatus may provide for theinjection of a single fluid into one core plug, a single fluid into atleast two core plugs, multiple fluids into one core plug, and multiplefluids into at least two core plugs. The dual core flooding apparatusmay provide for the simultaneous injection of separate fluids into twocore plugs. The dual core flooding apparatus may provide for differentorientations of the core plugs, such as horizontal orientations,vertical orientations, and angled orientations. The dual core floodingapparatus may provide for the observation of injection fluids and thein-situ measurement during core flooding of density and viscosity atspecific reservoir conditions. The dual core flooding apparatus mayprovide for the separation and measurement of produced oil and waterfrom core plugs. Additionally, the dual core flooding apparatus mayprovide for the measurement of differential pressures across each testedcore plug during core flooding tests. The dual core flooding apparatusmay further provide accurate and stable pore pressures in each testedcore plug and accurate and stable confining pressures in each coreholder.

Dual Core Flooding Apparatus

FIG. 1. depicts a dual core flooding apparatus 100 in accordance with anembodiment of the disclosure, The dual core flooding apparatus 100 mayinclude a first dual core holder 102 and a second dual core holder 104each arranged to hold a single core plug or composite core plug andreceive fluids from a fluids delivery system 106. In some embodiment,the core flooding apparatus 100 may include differential pressuremeasurement systems 108 and 110 coupled to the first dual core holder102 and the second dual core holder 104 respectively. In someembodiments, the core flooding apparatus 100 may include an imagecapture system 112.

As also shown in FIG. 1, in some embodiments, the dual core floodingapparatus 100 may include an automated confining pressure system 114coupled to the first core holder 102 and the second core holder 104. Insome embodiments, the dual core flooding apparatus 100 may include adensity and viscosity measurement system 116 coupled to the first coreholder 102. In some embodiments, the dual core flooding apparatus 100may include a first oil/water separation system 118, a first backpressure regulation system 120, a first effluent measurement system 122,a second oil/water separation system 124, a second back pressureregulation system 126, and a second effluent measurement system 128. Insome embodiments, the dual core flooding apparatus 100 may include adata acquisition and control system 130 coupled to various components ofthe apparatus 100

In some embodiments, the dual core flooding apparatus 100 may includeone or more ovens to provide heating for fluids, components, and otheraspects of the system 100. For example, as shown in FIG. 1, in someembodiments the dual core flooding apparatus 100 may include a firstoven 132 arranged to heat the fluids delivery system 106 and a secondoven 134 arranged to heat the first core holder 102, the second coreholder 104, the image capture system 112, the density and viscositymeasurement system 116, the first oil/water separation system 118, andthe second oil/water separation system 124. In some embodiments, thefirst oven 132 and the second oven 134 may be RAD/RFD cabinet ovensmanufactured by Despatch Industries of Minneapolis, Minn., USA.

As also shown in FIG. 1, data acquisition and control signal connectionsare represented by dashed lines. The data acquisition and control system130 may acquire data from components of the dual core flooding apparatus100 and may control components of the dual core flooding apparatus 100(for example, via control signals sent over a network to components ofthe dual core flooding apparatus 100). As further shown FIG. 1, fluidcommunication connections are represented by solid lines. As describedin the disclosure, various components of the dual core floodingapparatus 100 may be in fluid communication with one another via variousarrangements of valves, connectors, and other components.

As described further in the disclosure, the dual core flooding apparatus100 may enable the simulation of core flooding and physical displacementprocesses in oil and gas reservoirs at specific reservoir conditions(for example, temperature and pressure). The dual core floodingapparatus 100 may provide the simultaneous injection of separate fluidsinto two core plugs with varying dimensions and at an injection flowrate in the range of 0.001 cubic centimeters/minute (cc/min) to 15cc/min. The dual core flooding apparatus 100 may maintain an accurateand stable confining pressure of up to 10000 pounds-per-square inch(psi) and a pore pressure of up to 5000 psi. The dual core floodingapparatus 100 may further provide for an accurate and stable overburdenpressure. The dual core flooding apparatus 100 may provide for theobservation of injection fluid and the in-situ measurement during coreflooding of density and viscosity at specific reservoir conditions. Thedual core flooding apparatus 100 may further provide for the separationand measurement of produced oil and water from core plugs. Additionally,the dual core flooding apparatus 100 may provide for the measurement ofdifferential pressures across each tested core plug in the first coreholder and the second core holder during core flooding tests. Each ofthe components of the dual core flooding apparatus is further describedin detail.

Fluids Delivery System

FIGS. 2A-2D are schematic diagrams of the fluids delivery system 106 inaccordance with an example embodiment of the disclosure. The fluidsdelivery system 106 may deliver (for example, inject) fluids into coreplugs in the core holders 102 and 104 (and into core plugs in each coreholder 102 and 104) using one or more pumps and an arrangement of pistonaccumulators, connectors, and valves. In some embodiments, the fluidsdelivery system 106 may deliver one or more fluids at a constant flowrate in the range of 0.001 cc/min to 15 cc/min and at a working pressurein the range of 1 psi to 10,000 psi. It should be appreciated that FIGS.2A-2D depicts merely one embodiment of an arrangement and valves andconnectors of the fluids delivery system 106 and other embodiments mayinclude different arrangements of valves and connectors.

As shown in FIGS. 2A-2D, for example, in some embodiments the fluidsdelivery system 106 may include one or more fluid accumulators 201, 202,203, 204, and 205, and pumps 206 and 207. In some embodiments, the fluidaccumulators 201, 202, 203, 204, and 205 may be piston accumulatorsmanufactured by Coretest Systems, Inc., of Morgan Hill, Calif., USA. Insome embodiments, the fluid accumulators 201, 202, 203, 204, and 205 mayeach have a delivery volume of about 2 liters and a maximum workingpressure of about 10,000 psi. In some embodiments, the pumps 206 and 207may be Quizix Q5000 pumps manufactured by Chandler Engineering of Tulsa,Okla., USA. In some embodiments, the pumps 206 and 207 may have amaximum working pressure of 10,000 psi and a flow rate range of 0.0001milliliters (ml) ml/minute (min) to 15 ml/min.

The fluids delivery system 106 may include an arrangement of valves andconnectors to facilitate selective delivery of one or multiple fluids tothe first core holder 102, the second core holder 104, or both. Forexample, as shown in FIGS. 2A-2D, the first pump 206 may be connected tovalves 208 and 209. In some embodiments, valves 208 and 209 may bemanual valves. Similarly, the second pump 207 may be connected to valves210 and 211. In some embodiments, valves 210 and 211 may be manualvalves. The valve 209 coupled to the first pump 206 may be a drain valveto enable draining of the lines connected to the first pump 206. Thevalve 208 may connect the first pump 206 to the fluid accumulators 203,204, and 205 via the arrangement of valves and cross connectors depictedin FIGS. 2A-2D and described further infra. Similarly, the valve 210 mayconnect the second pump 207 to the fluid accumulators 203, 204, and 205and the valve 211 may connect the second pump 207 to the fluidaccumulators 201 and 202 via the arrangement of valves and crossconnectors depicted in FIGS. 2A-2D and described further infra.

As shown in FIGS. 2A-2D, the first pump 206 may be connected to thefluid accumulators 203, 204, and 205 via valves 212 and 213. The valves212 and 213 may be connected to the valve 208 and, in some embodiments,may be automatic valves. As also shown in FIG. 2, the second pump 207may be connected to the fluid accumulators 203, 204, and 205 via thevalves 214 and 215. The valves 214 and 215 may be connected to the valve210 and, in some embodiments, may be automatic valves.

The valves 212, 213, 214, and 215 may be connected to the fluidaccumulators 203, 204, and 205 via cross connectors 216 and 217 and thevalves 218 and 219, valves 220 and 221, valves 222 and 223, valves 224and 225, valves 226 and 227, and valves 228 and 229. In someembodiments, the valves 218 and 219, the valves 220 and 221, and thevalves 222 and 223 may be automatic valves. In some embodiments, thevalves 224 and 225, the valves 226 and 227, and the valves 228 and 229may be manual valves.

As shown in FIGS. 2A-2D, the second pump 207 may be connected to thefluid accumulators 201 and 202 via the valves 230 and 231. The valves230 and 231 may be connected to the valve 211 and, in some embodiments,may be automatic valves. The valves 230 and 231 may be connected to thefluid accumulators via the valves 232 and 233 and the valves 234 and235. In some embodiments, the valves 232 and 233 and the valves 234 and235 may be manual valves.

The outlets of the fluid accumulators 203, 204, and 205 may be connectedto other components of the system 100 via another arrangement of valvesand connectors, such as cross connectors 236 and 237. As shown in FIGS.2A-2D, for example, the fluid accumulator 203 may be connected to crossconnectors 236 and 237 by the valves 238 and 239 respectively, the fluidaccumulator 204 may be connected to cross connectors 236 and 237 by thevalves 240 and 241 respectively, and the fluid accumulator 205 may beconnected to cross connectors 236 and 237 by the valves 242 and 243respectively. In some embodiments, the valves 238 and 239, the valves240 and 241, and the valves 242 and 243 are manual valves.

As further shown in FIGS. 2A-2D, for example, the fluid accumulator 201may be connected to the valves 244 and 245, and the fluid accumulator202 may be connected to the valves 246 and 247. In some embodiments, thevalves 244 and 245, and the valves 246 and 247, are manual valves. Thevalve 245 may be connected to the automatic valve 248, and the valve 246may be connected to the automatic valve 249. The fluids delivery system106 also includes the valves 250 and 251. The automatic valves 248 and249 may be connected to the valve 250. In some embodiments, the valve251 may be drain valve. In some embodiments, the valves 250 and 251 aremanual valves. As also shown in FIGS. 2A-2D, the valves 250 and 251 maybe connected to the automatic valve 252, and the cross connector 236 maybe connected to the automatic valve 253.

The automatic valves 252 and 253 may be connected to the automaticvalves 254 and 255, which in turn are connected to the image capturesystem 112 and the second dual core holder 104 respectively, as shown byconnection blocks A and B and as described further in the disclosure.

Similarly, the cross connector 237 may be connected to the automaticvalves 256 and 257, which are turn are connected to the first coreholder 102 and the second core holder 104 respectively, as shown byconnection block C in FIG. 2A.

FIG. 2B depicts an example of the delivery of a single fluid into twocore plugs (that is, into a core plug in the first core holder 102 and acore plug in the second core holder 104) using the fluids deliverysystem 106. The fluid path is shown by dashed line 260 depicted in FIG.2B. As shown in FIG. 2, the pump 206 may be used to pressurize throughthe valve 208, through the automatic valve 213, through the connector217, and through the automatic valves 219 and 225 to the fluidaccumulator 203. The fluid is pumped from the fluid accumulator 203,through the valve 238, through the connector 236, and through theautomatic valve 253 to the automatic valves 254 and 255. Some of thefluid will flow through automatic valve 254 to the image capture system112 and then to the first core holder 102 (as shown by connection blockA in FIGS. 2B and 3), while the other portion of the fluid will flowthrough the automatic valve 255 to the second core holder 104 (as shownby connection block B in FIGS. 2B and 4B).

FIG. 2C depicts an example of the simultaneous injection of two fluidsinto one core plug (that is, into a core plug in the first core holder102) using the fluids delivery system 106. The fluid paths are shown bydashed lines 262 and 264 depicted in FIG. 2C. The first pump 206 may beused to deliver the first fluid from the fluid accumulator 203, and thesecond pump 207 may be used to deliver the second fluid from the fluidaccumulator 204. The first fluid may be injected using pump 206 topressurize through the valve 208, through the automatic valve 213,through the connector 217, and through the automatic valves 219 and 225to the fluid accumulator 203. The fluid is pumped from the fluidaccumulator 203, through the valve 238, through the connector 236, andthrough the automatic valve 253 to the automatic valves 254 and 255. Thefluid flows through valve 254 and valves 300 and 302 shown in FIG. 3 tothe image capture system 112 and then to the first core holder 102 (asshown by connection block A in FIG. 2C). The valve 255 may be closed toprevent fluid from being delivered to the second core holder 104 (asshown by connection block B in FIGS. 2C and 4C). The second fluid may beinjected using pump 207 to pressurize through the valve 210, through theautomatic valve 214, through the connector 216, and through the valves220 and 227 to the fluid accumulator 204. The fluid is pumped from thefluid accumulator 204, through the valve 241, through the connector 237,and through the automatic valve 256 to the first core holder 102 (asshown by connection block C in FIGS. 2C and 4C). The automatic valve 257may be closed to prevent the second fluid from being delivered to thesecond core holder 104.

FIG. 2D depicts an example of the simultaneous injection of a firstfluid into one core plug (that is, into a core plug in the first coreholder 102) and a second fluid into a second core plug (that is, into acore plug in the second core holder 104) using the fluids deliverysystem 106. The fluid paths are shown by dashed lines 266 and 268depicted in FIG. 2D. The first pump 206 may be used to deliver the firstfluid 266 from the fluid accumulator 203, and the second pump 207 may beused to deliver the second fluid 268 from the fluid accumulator 204. Thefirst fluid 266 may be injected using pump 206 to pressurize through thevalve 208, through the valve 213, through the connector 217, and throughthe automatic valves 219 and 225 to the fluid accumulator 203. The firstfluid 266 is pumped from the fluid accumulator 203, through the valve238, through the connector 236, and through the automatic valve 253 tothe automatic valve 254. As shown in FIG. 3 by connection block A anddiscussed infra, the fluid flows through automatic valve 254 to theimage capture system 112 and then to the first core holder 102. Thesecond fluid 268 may be injected using pump 207 to pressurize throughthe valve 210, through the automatic valve 214, through the connector216, and through the automatic valves 220 and 227 to the fluidaccumulator 204. The second fluid 268 is pumped from the fluidaccumulator 204, through the valve 241, through the connector 237, andthrough the automatic valve 257 to the second core holder 104(connection block C in FIGS. 2D and 4D). The valve 256 may be closed toprevent the second fluid from being delivered to the first core holder102.

Image Capture System

FIG. 3 depicts a schematic diagram of the image capture system 112 inaccordance with an example embodiment of the disclosure. The imagecapture system 112 may enable the monitoring and observation of fluidsor other substances (for example, chemical solutions such as foaminggels) before injection of the fluids or other substances into core plugsin the core holders 102 and 104. The image capture system 112 may be influid communication with the fluids delivery system 106 and the coreholder 102 and may include an arrangement of valves that route fluidthrough an observation cell or bypass the viewing cell. The imagecapture system 112 may be connected to the automatic valve 254, as shownby connection block A in FIGS. 2A-2D and FIG. 3. The automatic valve 254may be coupled to the valves 300 and 302 shown in FIG. 3. In someembodiments, the valves 300 and 302 are manual valves. In someembodiments, as shown by line 304, at least a portion of the fluidrouted to the image capture system 112 may be routed to the density andviscosity measurement system 116.

The image capture system 112 may include a camera 306, a viewing cell308, and a pump 310. In some embodiments, the camera 306 may be a camerahaving a charged-coupled device (CCD) image sensor. The pump 310 may beconnected to the valves 312 and 314. In some embodiments, the valves 312and 314 are manual valves. The viewing cell 308 may be connected to thevalve 316. In some embodiments, the viewing cell 308 may have a maximumoperating temperature of about 150° C. and a maximum working pressure ofabout 6000 psi. The valve 302 may be connected to the valve 318. Thevalves 302 and 318 may enable the bypass of the viewing cell 308. Insome embodiments, the valves 316 and 318 are manual valves. The valves316 and 318 may be connected to the automatic valves 320 and 322. Insome embodiments, the valves 320 and 322 are automatic valves. As shownby connection block D in FIG. 3 and FIGS. 4A-4D, the automatic valve 320may connect the image capture system to the first core holder 102, andthe automatic valve 322 may connect the image capture system to thesecond core holder 104. As shown by connection block D in FIG. 3 andFIGS. 4A-4D, the automatic valve 322 may couple the image capture system112 to the second core holder 104.

During testing of a core holder, injection fluid may be routed throughthe automatic valve 254 (shown in FIGS. 2A-2D by connection block A)through the valve 300, and into the viewing cell 308. The video camera306 may capture video, still images, or both of the fluid in the viewingcell 308 and provide the capture video, still images, or both to thedata acquisition and control system 130. The fluid may exit the viewingcell and be routed through the valve 316, through the automatic valve320, and to the first core holder 102, as shown by connection block D inFIG. 3 and FIGS. 4A-4D. The confining pressure in the viewing cell maybe controlled by the pump 310. In some embodiments, the pump 310 may behand pump. In some embodiments, the pump 310 may be used to equalize thepressure inside the viewing cell 308 with the pressure outside theviewing cell 308 to protect the viewing cell 308. To bypass the viewingcell 308, the fluid may be routed through the valve 302 and through thevalve 318, and then to the first core holder 102, the second core holder104, or both simultaneously, as shown by connection block D. To bypassthe viewing cell 308, the valve 300 and the valve 316 may be closed.

Core Holders

FIGS. 4A-4D are schematic diagrams of the first core holder 102, thesecond core holder 104, and other components in accordance with anexample embodiment of the disclosure. In some embodiments, the coreholders 102 and 104 may each be configured as a standard Hassler coreholder having a fixed axial confining stress. In some embodiments, eachcore holder 102 and 104 may have a sleeve material compatible with CO2injection and chemical solution injections and may have a hydrostaticloading condition. In some embodiments, the core holders 102 and 104 mayeach have a maximum working pressure of 10,000 psi. In some embodiments,the core holders 102 and 104 may each accommodate a core plug of up to3.8 centimeters (cm) in diameter and in the range of 5 cm to 45 cm inlength. In some embodiments, the core holders 102 and 104 may each havethree inlets and three outlets. The core holders 102 and 104 may alsoinclude various connections for pressure sensing and control, such asvia the automated confining pressure system 114. In some embodiments,the core holders 102 and 104 may each be adjusted relative to a verticalaxis, a horizontal axis, or both, and relative to each other. Forexample, in some embodiments the core holder 102 and the core holder 104may be adjusted to be horizontal and parallel. In some embodiments, thecore holder 102 and the core holder 104 may be adjusted to be vertical,parallel, and at angles. In some embodiments, the core holder 102 andthe core holder 104 may be vertical and at the same height.

As shown in FIGS. 4A-4D, each core holder 102 and 104 may be connectedto an arrangement of valves to control the delivery of fluid to the coreholders. For example, FIGS. 4A-4D illustrates the automatic valves 320and 322 (also depicted in FIG. 3 as shown by connection block D) andautomatic valves 256 and 257 (also depicted in FIGS. 2A-2D as shown byconnection block C) that receive and route fluids from other componentsof the dual core flooding apparatus 100.

The automatic valve 320 may be connected to the valves 408 and 410 andthe automatic valve 322 may connected to the valves 416 and 418. In someembodiments, the valves 408 and 410 and the valves 416 and 418 may bemanual valves. The automatic valve 256 may be connected to the valves412 and 414, and the automatic valve 257 may be connected to the valves420 and 422. In some embodiments, the valves 412 and 414 and the valves420 and 422 may be manual valves. As shown in FIG. 2, the core holders102 and 104 may be coupled to the automated confining pressure system114. The automated confining pressure system 114 is connected to thevalves 424 and 426. In some embodiments, the valves 424 and 426 aremanual valves. In some embodiments, automated confining pressure system114 may be a PCI-112 manufactured by Coretest Systems, Inc., of MorganHill, Calif., USA.

The core holders 102 and 104 may also be connected to an arrangement ofvalves to provide for connection to the differential pressuremeasurement systems 108 and 110. For example, as shown in FIG. 1, thefirst core holder 102 may be connected to valve 428 and valve 430. Insome embodiments, the valves 428 and 430 are stainless steel valves. Thefirst core holder 102 may also be connected to upstream pressuretransducer (USPT) 432 and downstream pressure transducer (DSPT) 434 viathe valves 428 and 430 respectively. Similarly, for example, the secondcore holder 104 may be connected to valve 436 and valve 438. In someembodiments, the valves 436 and 438 are stainless steel valves. Thesecond core holder 104 may also be connected to an USPT 440 and a DSPT442 via the valves 436 and 438 respectively. The first core holder 102may also be coupled to a Heise® gauge (HSG) 448, and the second coreholder 104 may also be coupled to an HSG 450.

The output of the core holders 102 and 104 may be routed through anarrangement of valves to other components of the dual core floodingapparatus 100. For example. FIGS. 4A-4D depict valves 452 and 454 andvalves 456 and 458. In some embodiments, the valves 452 and 454 andvalves 456 and 458 are manual valves that enable the bypass of the firstcore holder 102 and the second core holder 104. An outlet from the coreholder 102 and the valves 452 and 454 may be connected to valve 460, andan outlet from the core holder 104 and the valves 456 and 458 may beconnected to valve 462. In some embodiments, an outlet from the coreholder 104 may be connected to the second oil/water separation system124, as shown by connection line 464 and connection block E in FIGS.4A-4D and FIG. 9.

The outlets from the valves 460 and 462 may be connected to automaticvalves 466 and 468. The outlet from the automatic valve 466 may beconnected to the density and viscosity measurement system 116, as shownby connection block F in FIGS. 4A-4D and FIG. 7. The outlet from theautomatic valve 468 may be connected to a bypass of the density andviscosity measurement system 116, as also shown by connection block F.

FIG. 4B depicts an example of the injection of a single fluid into coreplug in the first core holder 102 and a core plug in the second coreholder 104. The example depicted in FIG. 4B corresponds to the exampleof the fluids delivery system 106 illustrated in FIG. 2B and describedsupra. As shown by dashed line 470, a portion of the fluid from theimage capture system 112 (as shown by connection block D in FIGS. 4A-4Dand FIG. 3) may be routed through valve 320 and through the valve 410 tothe first core holder 102. The fluid exiting the first core holder 102may be routed through the valve 460 and either through the automaticvalve 466 to the density and viscosity measurement system 116 or throughthe automatic valve 468 to bypass the density and viscosity measurementsystem 116 (as shown by connection block F in FIGS. 4A-4D and FIG. 7).As shown by dashed line 472, a portion of the same fluid from the imagecapture system 112 (as shown by connection block D in FIGS. 4B and 3)may be routed through automatic valve 322 and through the valve 416 tothe second core holder 104. As shown by dashed line 464 and connectionblock E in FIGS. 4B and 9, the fluid exiting the second core holder 104may be routed to the second oil/water separation system 124.

FIG. 4C depicts an example of the injection of the simultaneousinjection of two fluids into one core plug (that is, into a core plug inthe first core holder 102) using the fluids delivery system 106. Theexample depicted in FIG. 4C corresponds to the example of the fluidsdelivery system 106 illustrated in FIG. 2C and described supra. As shownby dashed line 474, a first fluid from the from the fluids deliverysystem 106 and image capture system 112 (as shown by connection block Ain FIG. 2C and FIG. 3, and connection block D in FIG. 3 and FIG. 4C) maybe routed through automatic valve 320 and through the valve 410 to thefirst core holder 102. As shown by dashed line 476, a second fluid fromthe fluids delivery system 106 (as shown by connection block C in FIG.2C and FIG. 4C) may be routed through automatic valve 256 and throughthe valve 412 to the first core holder 102. The fluids exiting the firstcore holder 102 may be routed through the valve 460 and either throughthe valve 466 to the density and viscosity measurement system 116 orthrough the automatic valve 468 to bypass the density and viscositymeasurement system 116, as shown by connection block F in FIGS. 4C and7. In such embodiments, the automatic valve 257 may be closed to preventthe fluids from being routed to the second core holder 104. In anotherembodiment, both fluids may be routed to the first core holder 102according to the path shown by dashed line 474.

FIG. 4D depicts an example of the simultaneous injection of a firstfluid into one core plug (that is, into a core plug in the first coreholder 102) and a second fluid into a second core plug (that is, into acore plug in the second core holder 104). The example depicted in FIG.4D corresponds to the example of the fluids delivery system 106illustrated in FIG. 2D and described supra. As shown by dashed line 478,a first fluid from the image capture system 112 (as shown by connectionblock D in FIGS. 3 and 4D) may be routed through automatic valve 320 andthrough the valve 410 to the first core holder 102. The first fluid mayexit the first core holder 102 according to the route described supra.As shown by dashed line 480, the second fluid from the fluids deliverysystem 106 (as shown by connection block C in FIGS. 2D and 4D) may berouted through the automatic valve 257 and through the valve 420 to thesecond core holder 104. The second fluid may exit the second core holder104 according to the route described supra.

As discussed supra, in some embodiments the core holders 102 and 104 mayeach be adjusted relative to a vertical axis, a horizontal axis, orboth, and relative to each other. In some embodiments, the first coreholder 102 and the second core holder 104 may each be rotationallymounted on a fixture to enable rotation of the first core holder 102 andthe second core holder 104. In such embodiments, for example, the firstcore holder 102 and the second core holder 104 may be rotated between ahorizontal orientation (for example, at a 0° angle relative to ahorizontal axis) and a vertical position (for example, at a 90° anglerelative to a horizontal axis). In some embodiments, the first coreholder 102 may be at a different height than the second core holder 104(for example, in a horizontal orientation the first core holder 102 maybe above the second core holder 104).

FIGS. 4E-4M depict various orientations of the core holders 102 and 104in accordance with example embodiments of the disclosure. FIGS. 4E-4Malso depict delivery of fluids to the core holders 102 and 104 in thevarious orientations in accordance with the examples described supra andillustrated in FIGS. 4A-4D. It should be appreciated that FIGS. 4E-4Mdepict the core holders 102 and 104 and fluid flows but omit for claritythe other components of the dual core flooding apparatus 100.

FIGS. 4E-4G depict the core holders 102 and 104 in various orientationsand having a single fluid delivered to both core holders 102 and 104from the fluids delivery system 106, as shown by line 483. As also shownin FIGS. 4E-4G by line 484, the fluid exiting the first core holder 102may be directed to the first back pressure regulation system 120, asdescribed further in the disclosure. As shown in FIGS. 4E-4G by line485, the fluid exiting the second core holder 104 may be directed to thesecond back pressure regulation system 126, as also described further inthe disclosure.

FIG. 4E depicts a horizontal orientation 486 of the core holders 102 and104 in accordance with an example embodiment of the disclosure. In thehorizontal orientation 486, the first core holder 102 and the secondcore holder 104 may be parallel to each other and horizontal relative tothe earth, such that the inlet and outlet of the first core holder 102lie along the same horizontal axis and the inlet and outlet of thesecond core holder 104 lie along the same horizontal axis.

FIG. 4F depicts a vertical orientation 487 of the core holders 102 and104 in accordance with an example embodiment of the disclosure. In thevertical orientation 487, the first core holder 102 and the second coreholder 104 may be parallel to each other and vertical relative to theearth, such that the inlet and outlet of the first core holder 102 liealong the same vertical axis and the inlet and outlet of the second coreholder 104 lie along the same vertical axis.

FIG. 4G depicts an angled orientation 488 of the core holders 102 and104 in accordance with an example embodiment of the disclosure. In theangled orientation 488, the first core holder 102 and the second coreholder 104 may be parallel to each other and angled relative to theearth such that the centerline of each core holder 102 and 104 forms anangle 490 of less than 90° with a horizontal axis (indicated by line491). In some embodiments, the angle 490 may be 30° or 60°. In someembodiments, the core holders 102 and 104 may be continuously rotated toany angle between 0° and 90°.

FIGS. 4H-4J depict the core holder 102 in various orientations andhaving two fluids delivered to the core holder 102 from the fluidsdelivery system 106. For example, delivery of a first fluid is shown byline 492 and delivery of a second fluid is shown by line 493. As alsoshown in FIGS. 4H-4J by line 494, the fluids exiting the first coreholder 102 may be directed to the first back pressure regulation system120, as described further in the disclosure. It should be appreciatedthat the various orientations and delivery of two fluids to the firstcore holder 102 shown in FIGS. 4H-4J may also be implemented using thesecond core holder 104 instead of the first core holder 102.

FIG. 4H depicts the horizontal orientation 486 of the first core holders102 in accordance with an example embodiment of the disclosure. Aspreviously stated, in the horizontal orientation 486, the first coreholder 102 may be horizontal relative to the earth, such that the inletand outlet of the first core holder 102 lie along the same horizontalaxis.

FIG. 41 depicts the vertical orientation 487 of the first core holders102 in accordance with an example embodiment of the disclosure. Aspreviously stated, in the vertical orientation 487, the first coreholder 102 may be vertical relative to the earth, such that the inletand outlet of the first core holder 102 lie along the same verticalaxis.

FIG. 4J depicts the angled orientation 488 of the first core holder 102in accordance with an example embodiment of the disclosure. Aspreviously stated and as shown in FIG. 4J, the first core holder 102 maybe angled relative to the earth such that the centerline of the firstcore holder 102 forms the angle 490 of less than 90° with a horizontalaxis (indicated by line 491). In some embodiments, the angle 490 may be30° or 60°. In some embodiments, the first core holder 102 may becontinuously rotated to any angle between 0° and 90°.

FIGS. 4K-4M depict the core holders 102 and 104 in various orientationsand having a first fluid delivered to the first core holder 102 from thefluids delivery system 106, as shown by line 495, and a second fluiddelivered to the second core holder 104 from the fluids delivery system106, as shown by line 496. As also shown in FIGS. 4K-4M by line 497, thefirst fluid exiting the first core holder 102 may be directed to thefirst back pressure regulation system 120, as described further in thedisclosure. As shown in FIGS. 4K-4M by line 498, the second fluidexiting the second core holder 104 may be directed to the second backpressure regulation system 126, as also described further in thedisclosure.

FIG. 4K depicts the horizontal 4K-4M 486 of the core holders 102 and 104for the delivery of a first fluid to the first core holder 102 and asecond fluid to the second core holder 104 in accordance with an exampleembodiment of the disclosure. As described supra, In the horizontal4K-4M 486, the first core holder 102 and the second core holder 104 maybe parallel to each other and horizontal relative to the earth, suchthat the inlet and outlet of the first core holder 102 lie along thesame horizontal axis and the inlet and outlet of the second core holder104 lie along the same horizontal axis.

FIG. 4L depicts the vertical 4K-4M 487 of the core holders 102 and 104for the delivery of a first fluid to the first core holder 102 and asecond fluid to the second core holder 104 in accordance with an exampleembodiment of the disclosure. As described supra, In the vertical 4K-4M487, the first core holder 102 and the second core holder 104 may beparallel to each other and vertical relative to the earth, such that theinlet and outlet of the first core holder 102 lie along the samevertical axis and the inlet and outlet of the second core holder 104 liealong the same vertical axis.

FIG. 4M depicts an angled orientation 488 of the core holders 102 and104 for the delivery of a first fluid to the first core holder 102 and asecond fluid to the second core holder 104 in accordance with an exampleembodiment of the disclosure. In the angled orientation 488, the firstcore holder 102 and the second core holder 104 may be parallel to eachother and angled relative to the earth such that the centerline of eachcore holder 102 and 104 forms the angle 490 that is less than 90° with ahorizontal axis (indicated by line 491). As previously mentioned, insome embodiments, the angle 490 may be 30° or 60° and, in someembodiments, the core holders 102 and 104 may be continuously rotated toany angle between 0° and 90°.

Differential Pressure Measurement Systems

FIG. 5 depicts a schematic diagram of the first differential pressuremeasurement system 108 in accordance with an example embodiment of thedisclosure. The first differential pressure measurement system 108 mayinclude three levels of pressure transducers arranged to measure thedifferential pressure across the core plug in the first core holder, andthe inlet pressure and outlet pressure of the first core holder 102.

As shown in FIG. 5, the first core holder 102 may be connected to thefirst differential pressure measurement system 108 by the valves 428 and430. The fluid flow direction through the first core holder 102 isdepicted by directional arrow 500.

As shown in FIG. 5, the first differential pressure measurement system108 includes three levels of differential pressure transducers 502, 504,and 506 and the inlet (upstream) and outlet (downstream) pressuretransducers 432 and 434 to measure differential pressure across the coreplug in the first core holder 102 while running core floodingexperiments. In some embodiments, the inlet pressure transducer 432 andthe outlet pressure transducer 434 may be pressure transducersmanufactured by Quartzdyne of Salt Lake City, Utah, USA. In someembodiments, the inlet pressure transducer 432 and the outlet pressuretransducer 434 may be pressure transducers manufactured by SetraSystems, Inc. of Boxborough, Mass., USA. In some embodiments, thepressure transducers may have an accuracy of about 0.01%. In someembodiments, the pressure transducers 432 and 434 have a maximum workingpressure of about 10,000 psi.

In some embodiments, the differential pressure transducers 502, 504, and506 may be stainless steel transducers. In some embodiments, thedifferential pressure transducers 502, 504, and 506 may have an accuracyof about 0.5% or, in some embodiments, about 0.1%. In some embodiments,the first pressure transducer 502 may have a range of 0 psid to 5 psid,the second pressure transducer 504 may have a range of 0 psid to 50psid, and the third pressure transducer 506 may have a range of 0 psidto 500 psid. In some embodiments, the differential pressure transducers502, 504, and 506 may be Barton Instruments pressure transducersmanufactured by Cameron International Corporation of Houston, Tex., USA.In some embodiments, the differential pressure transducers 502, 504, and506 may be Barton Instruments pressure transducers manufactured byCameron International Corporation of Houston, Tex., USA. In someembodiments, the differential pressure transducers 502, 504, and 506manufactured by Validyne Engineering of Northridge, Calif., USA.

FIG. 5 also depicts an arrangement of cross connectors 508 that connectthe valves and transducers in the manner depicted in the figure. Thefirst differential pressure measurement system 108 includes valves 510,512, and 514 that operate as filling and flushing valves for the firstdifferential pressure measurement system 108. Each differential pressuretransducer may be connected to bypass valves to protect the differentialpressure transducers from overpressure conditions. For example, thedifferential pressure transducer 502 may be connected to valves 516 and518. Similarly, the differential pressure transducer 504 may beconnected to valves 520 and 522, and the differential pressuretransducer 506 may be connected to valves 524 and 526. For example, ifthe first differential pressure transducer 502 detects an overpressurecondition, the valve 516 connected to the upstream pressure source maybe automatically opened to connect the negative side of the transducer502 to the upstream pressure source. The valve 518 may be automaticallyclosed to isolate the transducer 502 to the downstream pressure source,such that both sides of the transducer 502 are opened to the upstreampressure source and the differential pressure will be zero to protectthe transducer 502. The valve 522 may be automatically opened such thatthe second differential pressure transducer 504 having the greaterpressure range may be engaged to measure the differential pressure. Thevalves 520, 522, 524, and 526 may thus operate in a similar manner toprotect the valves 504 and 506 from overpressure conditions and engagethe third differential pressure transducer 506 to measure thedifferential pressure.

FIG. 6 depicts a schematic diagram of the second differential pressuremeasurement system 110 in accordance with an example embodiment of thedisclosure. As will be appreciated, the second differential pressuremeasurement system 110 may include similar components to that of thefirst differential pressure measurement system 108 and may operate in asimilar manner. The second differential pressure measurement system 110may include pressure transducers arranged to measure the pore pressure(that is, the inlet pressure of the core plug in the second core holder104), the inlet pressure and outlet pressure of the second core holder104, and the differential pressure across the core plug in the secondcore holder 104 during testing.

As shown in FIG. 6, the second core holder 104 may be connected to thesecond differential pressure measurement system 110 by the valves 436and 438. The fluid flow direction through the second core holder 104 isdepicted by directional arrow 600.

As depicted in FIG. 6, the second differential pressure measurementsystem 110 includes three levels of differential pressure transducers602, 604, and 606 to measure differential pressure across the core plugin the second core holder 104, and the inlet and outlet pressuretransducers 440 and 442 to measure upstream and downstream pressures forthe second core holder 104 while running core flooding experiments. Insome embodiments, the inlet pressure transducer 440 and the outletpressure transducer 442 may be pressure transducers manufactured byQuartzdyne of Salt Lake City, Utah, USA. In some embodiments, thepressure transducers may have an accuracy of about 0.01%. In someembodiments, the differential pressure transducers 602, 604, and 606 maybe stainless steel transducers. In some embodiments, the differentialpressure transducers 602, 604, and 606 may have an accuracy of about0.5%. In some embodiments, the first pressure transducer 602 may have arange of 0 psid to 5 psid, the second pressure transducer 604 may have arange of 0 psid to 50 psid, and the third pressure transducer 606 mayhave a range of 0 psid to 500 psid.

FIG. 6 also depicts an arrangement of cross connectors 608 that connectthe valves and transducers in the manner depicted in the figure. As alsoshown in FIG. 6, the second differential pressure measurement system 110includes valves 610, 612, and 614 that operate as filling and flushingvalves for the second differential pressure measurement system 110. Eachdifferential pressure transducer may be connected to bypass valves toprotect the differential pressure transducers from overpressureconditions. For example, the differential pressure transducer 602 may beconnected to automatic valves 616 and 618. Similarly, the differentialpressure transducer 604 may be connected to automatic valves 620 and622, and the differential pressure transducer 606 may be connected tovalves 624 and 626. For example, if the first differential pressuretransducer 602 detects an overpressure condition, the automatic valve616 connected to the upstream pressure source may be automaticallyopened to connect the negative side of the transducer 602 to theupstream pressure source. The automatic valve 618 may be automaticallyclosed to isolate the transducer 602 to the downstream pressure source,such that both sides of the transducer 602 are opened to the upstreampressure source and the differential pressure will be zero to protectthe transducer. The automatic valve 622 may be automatically opened suchthat the second differential pressure transducer 604 having the greaterpressure range may be engaged to measure the differential pressure. Theautomatic valves 620, 622, 624, and 626 may thus operate in a similarmanner to protect the valves 604 and 606 from overpressure conditionsand engage the third differential pressure transducer 606 to measure thedifferential pressure.

Density and Viscosity Measurement System

FIG. 7 depicts a schematic diagram of the density and viscositymeasurement system 116 in accordance with an example embodiment of thedisclosure. The density and viscosity measurement system 116 may beconnected to the first core holder 102 via the automatic valves 466 and468, as shown by connection block F in FIGS. 4A-4D and FIG. 7. Thedensity and viscosity measurement system 116 may include a density meter700 and a viscosity meter 702. The density meter 700 may be connected tovalves 704 and 706 and valves 708 and 710. In some embodiments, thedensity meter 700 may be an mPDS 2000V3 Evaluation Unit and a DMA512P/DMA HPM external Density Cell manufactured by Anon-Paar USA Inc.,of Ashland, Va., USA. In some embodiments, the density meter 700 mayhave a maximum working pressure of about 20,000 psi, a temperature rangeof about −10° C. to about 200° C., a measurement range of about 0 g/cm³to about 3 g/cm³, and an accuracy of about 0.0001 g/cm³.

In some embodiments, the valves 704 and 706 and the valves 708 and 710may be manual valves. The density and viscosity measurement system 116may also include a bypass valve 712 to enable bypassing the densitymeter 700. The valve 708 may be connected to the automatic valves 714and 716. In some embodiments, the valves 714 and 716 are automaticvalves.

The viscosity meter 702 may be connected to the automatic valve 714. Thedensity and viscosity measurement system 116 may include a differentialpressure transducer 718 to measure differential pressure across theviscosity meter 702. The outlet from the viscosity meter may be coupledto the valves 720 and 722. In some embodiments, the viscosity meter 702may be a Cambridge Viscosity viscosity meter manufactured by PAC ofHouston, Tex., USA.

The density and viscosity measurement system 116 may include anarrangement of valves to direct the fluids exiting the density meter700, the viscosity meter 702, and the bypass. For example, as shown inFIG. 7, the density and viscosity measurement system 116 may includeautomatic valves 724 and 726 and automatic valves 728 and 730. Theoutlet from the automatic valve 728 may be connected to the first backpressure regulation system 120, as shown by connection block G in FIGS.7 and 10, and the outlet from the automatic valve 730 may be connectedto the first oil/water separation system 118, as shown by connectionblock H in FIGS. 7 and 8. The valve 468 may provide for a bypass of thedensity meter 700 and the viscosity meter 702. The automatic valves 716and 726 may provide for a bypass of the viscosity meter 702.

To measure density, viscosity, or both, fluid may be routed from thefirst core holder 102 or the second core holder 104 through the valve466, through the valve 704, and to the density meter 700. Fluid exitingthe density meter 700 may be routed through the valve 708 to theautomatic valve 714 to the viscosity meter 702. The fluid exiting theviscosity meter 702 may be routed through the valve 722, through theautomatic valve 724, and through the automatic valve 728 to the firstback pressure regulation system 120 (as shown by connection block G) andthrough the automatic valve 730 to the first oil/water separation system118 (as shown by connection block H).

Oil/Water Separators

FIG. 8 is a schematic diagram of the first oil/water separation system118 in accordance with an example embodiment of the disclosure. Thefirst oil/water separation system 118 may be used to separate oil andwater in fluid from the first core holder 102 for subsequent measurementof the oil and water. In some embodiments, the first oil/waterseparation system 118 includes a gravity-based two-phase high pressureseparator 800 having a first phase 802 and a second phase 804. In someembodiments, the separator 800 may be an SFS-032 two phase sonic fluidseparator manufactured by Coretest Systems, Inc., of Morgan Hill,Calif., USA. In some embodiments, the separator 800 may have a maximumworking pressure of about 10,000 psi, a maximum temperature of about150° C., a total volume of about 4900 ml, a maximum change of watervolume of about 200 ml, a maximum change of oil volume of about 200 ml,a bore diameter of about 25.4 mm, and a bore length of about 384.82 mm.

As shown in FIGS. 7 and 8 and connection block H, the first oil/waterseparation system 118 may be connected to the density and viscositymeasurement system 116. The automatic valve 730 of the density andviscosity measurement system 116 may be connected to valves 806 and 808shown in FIG. 8. In some embodiments, the automatic valves 806 and 808are automatic valves. The automatic valve 806 may be connected to thefirst phase 802 of the separator 800. In some embodiments, the firstphase 802 of the separator 800 may be connected to valve 810. In someembodiments, valve 810 is a stainless steel valve. The automatic valve808 may provide as a bypass to the separator 800 and may be coupled toconnector 812 at the output of the first oil/water separation system118.

The outlet from the separator 800 may be coupled to automatic valves 814and 816. For example, one separated phase may be output via automaticvalve 814, and the other separated phase may be output via automaticvalve 816. The outlets from automatic valves 814 and 816 may beconnected to the connector 812, and the output from the connector 812may be provided to the first back pressure regulation system 120, asshown by connection block I in FIGS. 8 and 10.

The fluid from the density and viscosity measurement system 116 (or thebypass of the system 116) may be routed to the automatic valve 806 andthe first phase 802 of the oil/water separator 800. In some embodiments,the separator 800 may automatically measure the high of the oil column.Separated water from the bottom of the separator 800 may be routedthrough the automatic valve 816, through the connector 812, and to thefirst back pressure regulation system 120 for measurement by a balancedescribed further in the disclosure. In some embodiments, the effluentmeasurement system 122 may be used to measure oil and water production;in such embodiments, the fluid may be routed through the automatic valve808 to bypass the separator 800 and be provided directly to the firstback pressure regulation system 120, as shown by connection block I inFIGS. 8 and 10.

FIG. 9 depicts a schematic diagram of the second oil/water separationsystem 124 in accordance with an example embodiment of the disclosure.In some embodiments, the second oil/water separation system 124 may besimilar to the first oil/water separation system 118 and may include agravity-based two-phase high pressure separator 900 having a first phase902 and a second phase 904. The second oil/water separation system 124may be used to separate oil and water in fluid from the second coreholder 104 for subsequent measurement of the oil and water. In someembodiments, the second oil/water separation system 124 includes agravity-based two-phase high pressure separator 900 having a first phase902 and a second phase 904. In some embodiments, the separator 900 maybe an SFS-032 two phase sonic fluid separator manufactured by CoretestSystems, Inc., of Morgan Hill, Calif., USA.

As shown in FIG. 9 and FIGS. 4A-4D by connection block E, the secondoil/water separator may be connected to the second core holder 104. Theoutlet from the second core holder 104 may be connected to automaticvalves 906 and 908 shown in FIG. 9. In some embodiments, the valves 906and 908 are automatic valves. In some embodiments, some of the outputfrom the second core holder 104 may be provided to the second backpressure regulation system 126, as shown by line 910 and connectionblock J in FIGS. 9 and 10. The automatic valve 906 may be connected tothe first phase 902 of the separator 900. In some embodiments, the firstphase 902 of the separator may be connected to valve 912. In someembodiments, the valve 912 is a stainless steel valve. The valve 908 mayprovide a bypass to the separator 900 and may be connected to connector914 at the output of the second oil/water separation system 124.

The outlet from the separator 900 may be coupled to automatic valves 916and 918. For example, one separated phase may be output via automaticvalve 916, and the other separated phase may be output via automaticvalve 918. In some embodiments, the valves 916 and 918 may be automaticvalves. The outlets from automatic valves 916 and 918 may be connectedto the connector 914, and the output from the connector 914 may beprovided to the second back pressure regulation system 126, as shown byconnection block K in FIGS. 9 and 10.

A portion of the fluid from the second core holder 104 may be routed tothe valve 906 and the first phase 902 of the oil water separator.Another portion of the fluid from the second core holder 104 may berouted directly to the second back pressure regulation system 126, asshown by connection block J in FIGS. 9 and 10. In some embodiments, theseparator 900 may automatically measure the height of the oil column.Separated water from the bottom of the separator 900 may be routedthrough the automatic valve 918, through the connector 914, and to thesecond back pressure regulation system 126 for measurement by a balancedescribed further in the disclosure. In some embodiments, the secondeffluent measurement system 128 may be used to measure oil and waterproduction; in such embodiments, the fluid may be routed through thevalve 908 to bypass the separator 900 and be provided directly to thesecond back pressure regulation system 126 (as shown by connection blockK).

Back Pressure Regulation Systems

FIG. 10 is a schematic diagram of the first back pressure regulationsystem 120 and the second back pressure regulation system 126 inaccordance with an example embodiment of the disclosure. The first backpressure regulation system 120 and the second back pressure regulationsystem 126 (collectively referred to as the “dual back pressureregulation system”) may establish and control the pore pressure of coreplugs in the first core holder 102 and the second core holder 104 duringcore flooding and other tests.

As shown in FIG. 10, the first back pressure system 120 may include afirst back pressure regulator 1000 and the second back pressure system126 may include a second back pressure regulator 1002. Both the backpressure regulators 1000 and 1002 may be controlled by a back pressureregulator control system 1004. In some embodiments, the back pressureregulation control system 1004 may be manufactured by Coretest Systems,Inc., of Morgan Hill, Calif., USA.

The input to and output from the back pressure regulators 1000 and 1002may be controlled by an arrangement of valves and other components. Forexample, as shown in FIG. 10 and by connection block G in FIGS. 7 and10, automatic valve 1006 may be connected to the density and viscositymeasurement system 116. Similarly, as shown by connection block I inFIGS. 8 and 10, the automatic valve 1008 may be connected to the firstoil/water separation system 118. In some embodiments, the automaticvalves 1006 and 1008 are automatic valves. As also shown in FIGS. 9 and10 by connection block K, the automatic valve 1010 may be connected tothe second oil/water separator 124. Additionally, as shown by connectionblock J in FIGS. 9 and 10, the automatic valve 1012 may be connected tothe second core holder 104. In some embodiments, the automatic valves1010 and 1012 are automatic valves. The automatic valves 1006 and 1008may be connected to automatic valve 1014, and the automatic valves 1010and 1012 may be connected to the automatic valve 1016. The first backpressure regulator 1000 may be connected to the automatic valves 1006and 1008. The first back pressure regulation system 120 may also includea Heise® gauge 1018 connected to the first back pressure regulator 1000.The Heise® gauge 1018 may measure the expectant value of back pressureapplied by the first back pressure regulator 1000. The first backpressure regulator 1000 may be connected to the first effluentmeasurement system 122. The first back pressure regulator 1000 may beconnected to valves 1020 and 1022. In some embodiments, the valves 1020and 1022 are manual valves.

The second back pressure regulator 1002 may be connected to theautomatic valve 1016. The second back pressure regulation system 126 mayalso include a Heise® gauge 1024 connected to the second back pressureregulator 1002. The Heise® gauge 1024 may measure the expectant value ofback pressure applied by the second back pressure regulator 1002. Thesecond back pressure regulator 1002 may also be connected to valves 1026and 1028. In some embodiments, the valves 1026 and 1028 are manualvalves. The second back pressure regulator 1002 may also be connected tothe first effluent measurement system 128.

The back pressure regulator control system 1004 may be connected tovalves 1030 and 1032. In some embodiments, the valves 1030 and 1032 maybe manual valves. As shown in FIG. 10, the back pressure regulatorcontrol system 1004 may be connected to the first back pressureregulator 1000 via the valves 1030 and 1022. As also shown in FIG. 10,the back pressure regulator control system 1004 may be connected to thesecond back pressure regulator 1002 via the valves 1032 and 1026. Insome embodiments, the back pressure regulation control system 1004 maybe manufactured by Coretest Systems, Inc., of Morgan Hill, Calif., USA.In some embodiments, the back pressure regulation control system 1004may have a maximum working pressure of about 10,000 psi.

The first back pressure regulation system 120 may be used to set anexpectant value of back pressure before running core flooding tests.Produced fluid from the core plug in the first core holder 102 is routedthrough the automatic valve 1006 or the automatic valve 1008 against anexpectant pressure applied by the first back pressure regulator 1000such that pressure builds up in the core plug in the first core holder102 by the fluids delivery system 106. If the fluid pressure is greaterthan the expectant pressure applied by the back pressure regulator 1000,the fluid produced from the core plug in the first core holder 102 isrouted through the back pressure regulator 1000 to the first effluentmeasurement system 122 and to a balance or fraction collector.

The second back pressure regulation system 126 may be used to set anexpectant value of back pressure for the core plug in the second coreholder 104 before running core flooding tests. Produced fluid from thecore plug in the second core holder 104 is routed through the automaticvalve 1010 or the valve 1012 against an expectant pressure applied bythe second back pressure regulator 1004 such that pressure builds up inthe core plug in the second core holder 104 by the fluids deliverysystem 106. If the fluid pressure is greater than the expectant pressureapplied by the back pressure regulator 1004, the fluid produced from thecore plug in the second core holder 104 is routed through the backpressure regulator 1004 to the second effluent measurement system 128and to a balance or fraction collector.

Automated Confining Pressure System

FIG. 11 is a schematic diagram of the automated confining pressuresystem 114 in accordance with an example embodiment of the disclosure.The automated confining pressure system 114 may include an automaticpneumatic control intensifier (PCI) 1100, air regulators 1102 and 1104,a drain reservoir 1106, a water reservoir 1108 (for example, a deionizedwater reservoir), an overpressure burst disk 1110, a pressure transducer1112, and gauges 1114, 1116, and 1118. In some embodiments, theautomated confining pressure system 114 may be manufactured by CoretestSystems, Inc., of Morgan Hill, Calif., USA.

The automated confining pressure system 114 and components thereof maybe connected to the first core holder 102 and the second core holder 104via an arrangement of valves. For example, as shown in FIG. 11, firstcore holder may be connected to valves 1120, 1122, and 1124. In someembodiments, the valve 1120 may be a stainless steel valve. In someembodiments, the valves 1122 and 1124 may be manual valves. As alsoshown in FIG. 11, the second core holder 104 may be connected to valves1126, 1128, and 1130. In some embodiments, the valve 1126 may be astainless steel valve. In some embodiments, the valves 1128 and 1130 maybe manual valves.

The valve 1120 may be connected to valve 1132, and the valve 1126 may beconnected to valve 1134. In some embodiments, the valves 1132 and 1134are manual valves. The valves 1132 and 1134 may be connected to thedrain reservoir 1106 via connector 1136.

The valve 1122 may connected to valve 1138, and the valve 1128 may beconnected to valve 1140. In some embodiments, the valves 1138 and 1140are connected to the overpressure burst disk 1110. In some embodiments,the overpressure burst disk 1110 may be a 6000 psi burst disk. Theautomatic pneumatic control intensifier 1100 may be connected toautomatic valves 1142 and 1144. In some embodiments, the valves 1142 and1144 may be automatic valves. The automatic valve 1142 may be connectedto the valve 1146. In some embodiments, the valve 1146 may be astainless steel valve. The automatic pneumatic control intensifier 1100the transducer 1112, the water reservoir 1108 and other components maybe connected via the connectors 1148, 1150, and 1152, and the valve1154, as shown in FIG. 11. In some embodiments, the valve 154 may be amanual valve.

The automatic pneumatic control intensifier 1100 may have amultiplication in the range of 100:1 with a minimum required airpressure of 80 psi. The automatic pneumatic control intensifier 1100 mayhave a drive pressure in the range of 0 psi to 100 psi and an outletpressure in the range of 400 psi to 10000 psi for confining pressure. Toset the confining pressure in the first core holder 102, the valve 1138and the valve 1122 may be used to connect the automated confiningpressure system 114 to the first core holder 102. To set the confiningpressure in the second core holder 104, the valve 1140 and the valve1128 may be used to connect the automated confining pressure system 114to the second core holder 104. The confining pressure of the first coreholder 102 and the second core holder 104 may be set independently andsimultaneously.

Effluent Measurement Systems

FIG. 12 is a schematic diagram of the first effluent measurement system122 in accordance with an example embodiment of the disclosure. Thefirst effluent measurement system 122 may include a gas meter 1200,automatic valves 1202 and 1204, a balance 1206, and a fraction collector1208. The produced effluents from the first core holder 102 may berouted through the first back pressure regulator 1000 to the firsteffluent measurement system 122. The produced effluents may be routedthrough the automatic valve 1204 to the fraction collector 1208. Forexample, if a liquid/gas displacement test is performed, such as bydisplacing oil by CO₂, the fraction collector 1208 may be used tomeasure the produced liquid and the gas meter 1200 may measure producedgas. If the balance is used to measure effluent production, the producedeffluents may be routed through the automatic valve 1202 to the balance1206 and the automatic valve 1204 may be closed.

FIG. 13 depicts a schematic diagram of the second effluent measurementsystem 128 in accordance with an example embodiment of the disclosure.The second effluent measurement system 128 may include a gas meter 1300,automatic valves 1302 and 1304, a balance 1306, and a fraction collector1308. The produced effluents from the second core holder 104 may berouted through the second back pressure regulator 1004 to the secondeffluent measurement system 128. The produced effluents may be routedthrough the automatic valve 1302 to the fraction collector 1308. Forexample, if a liquid/gas displacement test is performed, such as bydisplacing oil by CO₂, the fraction collector 1308 may be used tomeasure the produced liquid and the gas meter 1300 may measure producedgas. If the balance is used to measure effluent production, the producedeffluents may be routed through the automatic valve 1302 to the balance1306 and the automatic valve 1304 may be closed.

Image Capture System and Core Holder Bypass

In some embodiments, the initial properties of an injection fluid may bemeasured before injection into a core plug in a core holder. FIG. 14 isa schematic diagram of the bypass of the image capture system 112 andthe first core holder 102 to enable measurement of the initialproperties of an injection fluid in accordance with an exampleembodiment of the disclosure. As shown by connection block A in FIG. 14and FIGS. 2A-2D, fluid may be routed from the fluids delivery system 106to the automatic valve 254 and to the bypass valve 1400. Fluid may thenbe routed via the bypass valve 1400 to the density and viscositymeasurement system 116, as shown by connection block F in FIGS. 7 and14. The initial properties of the fluid may thus be measured by thedensity and viscosity measurement system 116 after bypassing the imagecapture system 116 and the first core holder 102. The valve 720 shown inFIG. 7 and discussed supra may be a drain valve for the bypassed fluid.In some embodiments, the initial property of the injection fluid may bemeasured at a specific pressure by connecting the first back pressureregulation system 120 to the valve 720.

Data Acquisition System and Control System

FIG. 15 depicts a block diagram of the data acquisition and controlsystem 130 in accordance with an example embodiment of the disclosure.The data acquisition system 130 may include a data acquisition andcontrol processor 1502, a memory 1504, a data acquisition interface1506, and a device control interface 1512. In some embodiments, the dataacquisition system 130 may also include a network interface 1508. Insome embodiments, the data acquisition and control system 130 mayinclude a personal computer, such as a desktop computer, a laptopcomputer, a tablet computer, or the like.

The data acquisition system 130 may acquire data from various componentsof the dual core flooding apparatus 100, such as the fluids deliverysystem 106, the image capture system 112, the differential pressuremeasurement systems 108 and 110, the density and viscosity measurementsystem 116, the oil/water separators 118 and 124, the back pressureregulation systems 120 and 126, and the automated confining pressuresystem 114. In some embodiments, the data acquisition system 130 mayinclude a personal computer, such as a desktop computer, a laptopcomputer, a tablet computer, or the like.

The data acquisition and control processor 1502 (as used the disclosure,the term “processor” encompasses microprocessors) may include one ormore processors having the capability to receive and process data fromsensors of the data acquisition system 130. In some embodiments, theprocessor 1502 may include an application-specific integrated circuit(AISC). In some embodiments, the data acquisition processor 1502 mayinclude a reduced instruction set (RISC) processor. Additionally, theprocessor 1502 may include a single-core processors and multicoreprocessors and may include graphics processors. Multiple processors maybe employed to provide for parallel or sequential execution of one ormore of the techniques described in the disclosure. In some embodiments,the processor 1502 may include, for example, a first data acquisitionprocessor for data acquisition functions and a control processor forcontrol functions. The processor 1502 may receive instructions and datafrom a memory (for example, memory 1504).

The memory 1504 (which may include one or more tangible non-transitorycomputer readable storage mediums) of the data acquisition system 130may include volatile memory, such as random access memory (RAM), andnon-volatile memory, such as ROM, flash memory, a hard drive, any othersuitable optical, magnetic, or solid-state storage medium, or acombination thereof. The memory 1504 may be accessible by the processor1502 and may store executable computer code. The executable computercode may include computer program instructions for implementing one ormore techniques described in the disclosure, For example, the executablecomputer code may include data acquisition instructions 1516 executableby a processor (for example, the processor 1502) to implement one ormore embodiments of the present disclosure. In some embodiments, thedata acquisition instructions 1516 may include instructions foracquiring data from sensors of the data acquisition system 130 via thedata acquisition interface 1506 and processing the acquired data (forexample, converting the data from analog data to digital data). In someembodiments, the processing may include comparing an acquired data value(for example, a pressure value) to a threshold value and providing anotification based on the comparison.

In another example, the executable computer code may include dual coreapparatus control instructions 1518. For example, the dual core floodingapparatus control instructions 1518 may include instruction forcontrolling the fluids delivery system 106, the image capture system112, the differential pressure measurement systems 108 and 110, thedensity and viscosity measurement system 116, the oil/water separators118 and 124, the back pressure regulation systems 120 and 126, theautomated confining pressure system 114, or any combination thereof, inthe manner described in the disclosure to analyze the flow status ofcore plugs in the core holder 102, core holder 104, or both. Suchinstructions may include instruction to send control signals to, forexample, valves of the dual core flooding apparatus 100, to pumps of thedual core flooding apparatus 100, the back pressure regulation system1004, the automatic pneumatic control intensifier 1100, and othercomponents described in the disclosure. In some embodiments, theprocessing may include comparing a data value (for example, a pressurevalue) to a threshold value and providing a notification based on thecomparison. In some embodiments, the processing may include comparing adata value (for example, a pressure value) to a threshold value andperforming an action (for example, closing one or more valves, changingthe speed of a pump, and so on) based on the comparison.

The data acquisition interface 1506 (which may include one or moreinterfaces) may provide for communication between the data acquisitionsystem 130 and components (for example, sensors) of the dual coreflooding apparatus 100. For example, the data acquisition interface 1506may include circuitry for communication with pressure transducers, thecamera 306, the density meter 700, the viscosity meter 702, theseparators 800 and 900, the back pressure regulators 1000 and 1004, andother components of the dual core flooding apparatus 100. The dataacquisition interface 1506 may include a wired interface or a wirelessinterface and may for communication over wired networks or wirelessnetworks. In some embodiments, the data acquisition interface 1506 mayenable communication over industrial control networks. The dataacquisition interface 1506 may provide for communication using suitablestandards, protocols, and technologies, such as serial communicationprotocols (for example, Modbus), Industrial Ethernet (IE), the CommonIndustrial Protocol (CIP), and the like.

The network interface 1508 may provide for communication between thedata acquisition system 130 and other devices, such as the controlsystem 1500. In some embodiments, the network interface 1506 and dataacquisition interface 1506 may be combined. The network interface 1508may include a wired network interface card (NIC), a wireless (forexample, radio frequency) network interface card, or combinationthereof. The network interface 1508 may include circuitry for receivingand sending signals to and from communications networks, such as anantenna system, an RF transceiver, an amplifier, a tuner, an oscillator,a digital signal processor, and so forth. The network interface 1508 maycommunicate with networks (for example, network 504), such as theInternet, an intranet, a wide area network (WAN), a local area network(LAN), a metropolitan area network (MAN) or other networks.Communication over networks may use suitable standards, protocols, andtechnologies, such as Ethernet Bluetooth, Wireless Fidelity (Wi-Fi) (forexample, IEEE 802.11 standards), and other standards, protocols, andtechnologies. In some embodiments, the network interface 1508 may enablecommunication over industrial control networks.

The display 1510 may include a cathode ray tube (CRT) display, liquidcrystal display (LCD), an organic light emitting diode (OLED) display,or other suitable display. The display 1510 may display a user interface(for example, a graphical user interface) that may display data acquiredfrom components of the received from the dual core flooding apparatus100. In accordance with some embodiments, the display 1510 may be atouch screen and may include or be provided with touch sensitiveelements through which a user may interact with the user interface. Insome embodiments, the display 1510 may display a notification, such asalert, if data received from the components of the dual core floodingapparatus 100 meet a condition. For example, a notification may bedisplayed if a pressure value acquired from a pressure transducerexceeds a threshold value.

The data acquisition and control system 130 may also provide controlsignals to components of the dual core flooding apparatus 100. Forexample, the data acquisition and control system 130 may provide controlsignals to the fluids delivery system 106, the image capture system 112,the differential pressure measurement systems 108 and 110, the densityand viscosity measurement system 116, the oil/water separators 118 and124, the back pressure regulation systems 120 and 126, the automatedconfining pressure system 114, or any combination thereof.

The device control interface 1512 (which may include one or moreinterfaces) may provide for communication between the data acquisitionsystem 130 and controllable devices (for example, valves, pumps, and thelike) of the dual core flooding apparatus 100. For example, the devicecontrol interface 1512 may include circuitry for sending control signalsto valves, pumps, the camera 306, automated confining pressure system114, the back pressure regulation control system 1004 and other devicesof the dual core flooding apparatus 100. The device control interface1512 may include a wired interface or a wireless interface and may forcommunication over wired networks or wireless networks. In someembodiments, the device control interface 1512 may enable communicationover industrial control networks. The device control interface 1512 mayprovide for communication using suitable standards, protocols, andtechnologies, such as serial communication protocols (for example,Modbus), Industrial Ethernet (IE), the Common Industrial Protocol (CIP),and the like.

In some embodiments, the data acquisition and control system 130 may becoupled to an input device 1520 (for example, one or more inputdevices). The input devices 1520 may include, for example, a keyboard, amouse, a microphone, or other input devices. In some embodiments, theinput device 1520 may enable interaction with a user interface displayedon the display 1510. For example, in some embodiments, the input devices1520 may provide for the input of values (for example, pressure values,flow rates, and the like) to directly or indirectly control componentsof the dual core flooding apparatus 100.

Alternatively, in some embodiments, the data acquisition and controlsystem 130 may be implemented in multiple systems or devices, such thatdata acquisition functions are performed by a first system or device andcontrol functions are performed by a second system or device. Suchseparated systems or devices may have similar components to the dataacquisition system 130. In some embodiments, the data acquisition system130 may be a part of an industrial control system (such as a SupervisoryControl and Data Acquisition System (SCADA)), a distributed controlsystem (DSC) or other similar systems.

EXAMPLES

The following examples are included to demonstrate embodiments of thedisclosure. It should be appreciated by those of skill in the art thatthe techniques and compositions disclosed in the example which followsrepresents techniques and compositions discovered to function well inthe practice of the disclosure, and thus can be considered to constitutemodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or a similar result without departing from the spirit and scope ofthe disclosure.

In some embodiments, the dual core flooding apparatus 100 may be used toinvestigate different oil recovery techniques, including secondary andtertiary oil recovery processes. For example, oil recovery during waterand CO2 into a heterogeneous reservoir may be limited as a result of anearly breakthrough of water and CO2 caused by viscous fingering andgravity override such that poor displacement efficiencies occurs.Accordingly, in some embodiments, the dual core flooding apparatus 100may be used to study the impact of reservoir heterogeneity on oilrecovery by seawater and CO2 flooding by, for example, seawater and CO2injections, thermal foam slug injections, and post-seawater and post-CO2injections. In the core flooding tests described infra, live oil, deadcrude oil, seawater, and supercritical CO2 were used. The core floodingtests were conducted at a temperature of 212° F., a pore pressure of3200 psi, and a confining pressure of 4500 psi.

In the example experiment, two core plugs were selected: a highpermeable core plug (HPCP) and a low permeable core plug (LPCP). Thecore plugs were prepared by saturating the core plugs with brine (forexample, to determine the pore volume of the core plug), performingbrine permeability measurements, and then establishing initial water andoriginal oil saturation of the core plugs. The high permeable core plugwith initial water and original oil may be placed in to the first coreholder 102, and the low permeable core plug with initial water andoriginal oil were placed in the second core holder 104. Deionized waterwas filled in into the annulus between a rubber sleeve and the coreholders 102 and 104 via the automated confining pressure system 114 atambient conditions. All fluid lines (for example, inlet lines, outlines,pressure lines, and bypass lines) were connected to the core holders 102and 104, as shown in FIG. 4.

The automated confining pressure system was used to apply a confiningpressure of 1500 psi to both core holders 102 and 104. The back pressureregulation systems 120 and 126 were used to establish a pore pressure of500 psi of the core plugs in core holders 102 and 104 respectively. Thepore pressure was established by injecting dead crude oil at a flowrateof 1.0 cc/min at ambient temperatures using the first pump 206. The porepressure of the high permeable core plug in the first core holder 102was established by injecting the dead crude oil using the fluidsdelivery system 106 shown in FIG. 2A and routed via the followingcomponents: the first pump 206, the valves 208 and 213, the connector217, the valves 219 and 225, the accumulator 203, the valve 238, theconnector 236, the automatic valve 253, and the automatic valve 254. Thedead crude oil was routed to bypass the image capture system 112 shownin FIG. 3 via the valve 302 and the valve 318. The dead crude oil wasthen routed to the high permeable core plug via the inlet of the firstcore holder 102 shown in FIG. 4A via the automatic valve 320 and thevalve 410. The dead crude oil was routed from the outlet of the firstcore holder shown in FIG. 4A via the automatic valve 460 and the valve466 to the density and viscosity measurement system 116. The dead crudeoil was routed to bypass the density meter 700 and the viscosity meter702 via the valve 712, the automatic valve 716, the automatic valve 726,and the automatic valve 728 shown in FIG. 7. The dead crude oil was thenrouted to the first back pressure regulator 1000 via the valve 1006shown in FIG. 10 to first establish a pore pressure of 500 psi. Afterestablishing a pore pressure of 500 psi, a confining pressure of 2000psi was established using the automating confining pressure system 114and a pore pressure of 1000 psi was established using the back pressureregulator 1000. After establishing a confining pressure of 2000 psi anda pore pressure of 1000 psi, the confining pressure and pore pressurewere increased in increments of 500 psi until a confining pressure of4500 psi and a pore pressure of 3200 psi were established.

The pore pressure of the low permeable core plug in the second coreholder 104 was established by injecting the dead crude oil using thefluids delivery system 106 shown in FIG. 2A and the same routing pathdescribed supra to the automatic valves 254 and 255. After establishingthe confining pressure and pore pressure for the high permeable coreplug in the first core holder 102, the automatic valve 254 was closedand the confining pressure and pore pressure for the low permeable coreplug in the second core holder 104 were established by increasing theconfining pressure and pore pressure in increments of 500 psi. The deadcrude oil was routed from the automatic valve 255 to the valve 416 andto the second core holder 104, as shown by connection block B in FIGS.2A and FIG. 4A. The dead crude oil was routed from the low permeablecore plug via the outlet of the second core holder 104 to the secondoil/water separation system 124 via the valves 906 and 908 and then tothe second back pressure regulator 1002 via the automatic valve 1010 andthe automatic valve 1016 shown in FIG. 10 to first establish a porepressure of 500 psi. During the process of establishing the confiningpressure and pore pressure for the second core holder 104, the valves420, 422, 456, and 458 shown in FIG. 4A were all open and the automaticvalves 906, 908, and 918 shown in FIG. 9 were all open.

The dual core flooding apparatus 100 may be used to evaluate thewettability of the core plug, as the wettability of the core plug is afactor in influencing oil recovery by water, CO2, and chemical floodingprocess. The restoration of wettability of the core plug is used torestore the wettability at reservoir conditions for oil recoverystudies. An example experiment of the restoration of wettability of acore plug using the dual core flooding apparatus 100 is described infra.

The temperature of the second oven 134 was set to 102° C. and allowed tostabilize overnight to reach temperature equilibrium. The heating of thecomponents inside the second oven 134 may result in the expansion of thedead crude oil in the high permeable core plug (HPCP) and the lowpermeable core plug (LPCP). Constant pore pressures may be maintained bythe back pressure regulation systems 120 and 126, and a constantconfining pressure may be maintained by the automated confining pressuresystem 114.

Dead crude oil in the high permeable core plug (HPCP) and the lowpermeable core plug (LPCP) may be displaced using live oil in the amountof about 4 pore volume for each core plug and at a flow rate of about1.00 cc/min and an injection pressure greater than 3200 psi. The liveoil was injected using the fluids delivery system 106 shown in FIG. 2Aand the second pump 207 and fluid accumulator 201. The live oil wasinjected into the high permeable core plug in the first core holder 102via the second pump 207 and fluid accumulator 201 and by routing via thefollowing components shown in FIG. 2A: the second pump 207, the valve211, the automatic valve 230, the valve 233, the fluid accumulator 201,the valve 245, the automatic valve 248, the valve 250, the automaticvalve 252 and the automatic valve 254 (with the automatic valve 255being closed). The live oil was routed to through the image capturesystem 112 shown in FIG. 3 via the valve 300 and the valve 316. The liveoil was then routed to the high permeable core plug via the inlet of thefirst core holder 102 shown in FIG. 4A via the automatic valve 320 andthe valve 410. The live oil was routed from the high permeable core plugvia the outlet of the first core holder shown in FIG. 4A via the valve460 and the automatic valve 466 to the density and viscosity measurementsystem 116. The live oil was routed to bypass the density meter 700 andthe viscosity meter 702 via the valve 468, the automatic valve 728 andthe automatic valve 726, shown in FIG. 7. The live oil was then routedto the first back pressure regulator 1000 via the valve 1006 shown inFIG. 10. During the injection of live oil into the high permeable coreplug in the first core holder 102, the valves 412, 414, 452, and 454were closed, as shown in FIG. 4C.

The live oil may be injected into the low permeable core plug in thesecond core holder 104 at a flow rate of 1.0 cc/min and an injectionpressure greater than 3200 psi using the second pump 207 and the fluidaccumulator 201 of the fluids delivery system 106 and the same routingpath described supra to the automatic valves 254 and 255. The live oilwas routed from the automatic valve 255 (with the automatic valve 254closed) to the valve 416 and to the second core holder 104. The live oilwas routed from the outlet of the second core holder 104 to the secondoil/water separation system 124 via the automatic valves 906 and 908,the automatic valve 918, and then to the second back pressure regulator1002 via the automatic valve 1010, the valve 1012, and the automaticvalve 1016 shown in FIG. 10. During the injection of live oil into thehigh permeable core plug in the first core holder 102, the valves 420,422, 456, and 458 were closed.

The high permeable core plug and the low permeable core plug were agedabout three weeks in dead crude oil at ambient conditions and aboutthree weeks in the live crude oil at reservoir conditions of a porepressure of about 3200 psi and a temperature of about 102° C. to restorethe wettability of the core plugs. During the aging process, about onepore volume of live crude oil was injected each day to monitor injectionpressure and water production for correction of initial water andoriginal oil saturation. At the end of the aging process, differentialpressure across the core plugs and injection flow rates were recorded todetermine the effective oil permeability (K_(eo)). In this experiment ofaging the core plugs with dead crude oil and live crude oil, the highpermeable core plug and the low permeable core plug have a mixedwettability system (that is, slightly oil-wet).

The dual core flooding apparatus 100 may be also be used to performseawater flooding experiments to determine oil recovery factor,remaining oil saturation, and the performance of seawater flooding forboth the high permeable core plug and the low permeable core plug. Theseawater flooding test was conducted at reservoir conditions, a porepressure of 3200 psi, a confining pressure of 4500 psi, and atemperature of 102° C. The seawater injection flow rate was about 0.5cc/min. Before running the seawater flooding test, the live crude oil inthe inlet lines, bypass lines, and outlet lines of the core holders 102and 104 was cleaned out using injection seawater and the valves 412,414, 452, and 454 for the first core holder 102 and the valves 420, 422,456, and 458 for the core holder 104.

Seawater was injected simultaneously to both the high permeable coreplug in the first core holder 102 and the low permeable core plug in thesecond core holder 104 using the first pump 206 and the fluidaccumulator 204 of the fluids delivery system 106. The seawater wasinjected into the high permeable core plug in the first core holder 102and the low permeable core plug in the second core holder 104 by routingthe seawater via the following components shown in FIG. 2A: the firstpump 206, the valve 208, the automatic valve 212, the connector 216, theautomatic valve 220, the valve 227, the fluid accumulator 204, the valve240, the connector 236, the valve 253, and the automatic valve 254 opento the high permeable core plug in the first core holder 102 and theautomatic valve 255 open to the low permeable core plug in the secondcore holder 104. The seawater was routed to bypass the image capturesystem 112 shown in FIG. 3 via the valve 302 and the valve 318 (and byclosing the valves 300 and 316). The seawater was then routed to thehigh permeable core plug via the inlet of the first core holder 102shown in FIG. 4A via the automatic valve 320 and the valve 410. Theseawater was routed from the high permeable core plug via the outlet ofthe first core holder 102 shown in FIG. 4A via the valve 460 and theautomatic valve 468 to the bypass of the density and viscositymeasurement system 116. The seawater was routed to bypass the densitymeter 700 and the viscosity meter 702 via the automatic valve 468 andthe automatic valve 730 shown in FIG. 7. The seawater was then routed tothe first oil/water separation system 118 via the valve 806 and into theseparator 800, where the amount of produced oil was measured. Theseawater was routed from the outlet of the separator 800 via theautomatic valve 816 and the automatic valve 1008 to the back pressureregulator 1000 shown in FIG. 10, where the seawater was routed to thefirst effluent measurement system 122 and the seawater production wasmeasured using the balance 1206 of the first effluent measurement system122.

The seawater was routed from the fluids delivery system 106 to the lowpermeable core plug in the second core holder 104 via the valve 255, asshown in FIG. 2. The seawater was then routed via the valve 416 shown inFIG. 4C to the low permeable core plug via the inlet of the second coreholder 104. The produced oil and seawater were routed from the lowpermeable core plug via the outlet of the second core holder 104 shownin FIG. 4A to the second oil/water separation system 124 via theautomatic valve 906 and into the separator 900 shown in FIG. 9, wherethe amount of produced oil was measured. The seawater was routed fromthe outlet of the separator 900 via the automatic valve 916 and theautomatic valves 1010 and 1016 to the back pressure regulator 1002 shownin FIG. 10, where the seawater was routed to the second effluentmeasurement system 128 and the seawater production was measured usingthe balance 1306 of the first effluent measurement system 128. Theseawater flooding test was finished when the water cut from either thehigh permeable core plug in the first core holder 102 or the lowpermeable core plug in the second core holder 104 reached 99%, at whichpoint the first pump 206 of the fluids delivery system 106 was stoppedand the automatic valve 253 was closed.

In some embodiments, supercritical CO2 may be injected after seawaterflooding to recover remaining oil. The dual core flooding apparatus 100may be also be used to perform CO2 flooding experiments after seawaterflooding experiments. A supercritical CO2 flooding experiment wasconducted by simultaneously injecting supercritical CO2, as a displacingagent, into the high permeable core plug in the first core holder 102and the low permeable core plug in the second core holder 104 andfollowed by water injection. The supercritical CO2 flooding test wasconducted at reservoir conditions of a pore pressure of about 3200 psiand a temperature of about 102°. The supercritical CO2 injection wasinjected simultaneously to both the high permeable core plug in thefirst core holder 102 and the low permeable core plug in the second coreholder 104 using the second pump 207 and the fluid accumulator 202 ofthe fluids delivery system 106. The second pump 207 was started in amode of pair constant pressure to establish the pump pressure the sameas the pore pressure of the core plugs in the core holders 102 and 104.The supercritical CO2 was routed via the valve 211, the automatic valve231, the valve 235, the fluid accumulator 202, the valve 246, theautomatic valve 249, the valve 250, and the automatic valve 252. Whenthe pressure on both sides of the automatic valve 252 reached the samepressure, the second pump 207 was stopped and the pump changed to pairconstant flow rate at the desired CO2 injection rate. The second pump207 was restarted and the automatic valve 252 was opened, and thesupercritical CO2 was routed via the automatic valve 254 open to thehigh permeable core plug in the first core holder 102 and the automaticvalve 255 open to the low permeable core plug in the second core holder104. The supercritical CO2 was routed to bypass the image capture system112 shown in FIG. 3 via the valve 302 and the valve 318 (and by closingthe valves 300 and 316). The supercritical CO2 was then routed to theinlet of the first core holder 102 shown in FIG. 4A via the automaticvalve 320 and the valve 410. The supercritical CO2 was routed via thevalve 416 to the inlet of the second core holder 104.

The produced oil, water, and CO2 were routed from the high permeablecore plug via the outlet of the first core holder 102 and low permeablecore plug via the outlet of the second core holder 104 in the same routedescribed supra for the produced oil, supercritical CO2, and seawater tofirst oil/water separation system 118 and the second oil waterseparation system 124 and then to the respective back pressureregulators 1000 and 1002. One pore volume of supercritical CO2 wasinjected simultaneously into the high permeable core plug in the firstcore holder 102 and the low permeable core plug in the second coreholder 104 at an expectant injection rate. During the supercritical CO2miscible flooding, the upstream pressure and the differential pressureacross the high permeable core plug and the low permeable core plug weremeasured using the differential pressure measurement systems 108 and 110and used to evaluate the recovery performance, determine effective orrelative permeability, and injectivity to supercritical CO2 at theremaining oil saturation (ROS) after the supercritical CO2 flooding.Additionally, the amount of oil may be measured by a gradate tube atambient conditions.

The direct injection of supercritical CO2 to displace crude oil maycause viscous fingering and supercritical CO2 override, and theunfavorable viscosity ratio between crude oil and supercritical CO2 maycause inefficient displacement during supercritical CO2 flooding.Thermal foam slug injection (TFSI) may be used to improve areal andvertical sweet efficiencies by plugging high permeable zones andstabilizing viscous fingering. The dual core flooding apparatus 100 maybe used to perform thermal foam slug injection experiments on core plugsin the first core holder 102 and second core holder 104. A thermal foamslug injection test was conducted after the supercritical CO2 floodingexperiment described supra. After the supercritical CO2 injection, theautomatic valves 254, 255, 252, and valves 250, 249, and 246 were closedand the fluid accumulator 202 was replaced with an external accumulatorhaving a thermal foam solution. The bottom valve of the externalaccumulator was connected to the valve 235 and the top valve of theexternal accumulator was connected to the valve 246. Before injection ofthe thermal foam solution into the high permeable core plug in the firstcore holder 102, the solution was evaluated using the image capturesystem 112 and the density and viscosity were measured using the densityand viscosity measurement system 116. During such evaluation andmeasurement, the first core holder 102 and first oil/water separationsystem 118 were bypassed, as shown in FIG. 14, and the thermal foamsolution was routed to the back pressure regulator 1000 shown in FIG.10. The low permeable core plug was isolated or open during the test.

The thermal foam solution was injected according to the followingprocedure. The valves 428 and 430 connecting the first differentialpressure measurement system 108 were closed and the bypass valves 412,414, and 454 were opened, as shown in FIG. 4. To build pressure in thethermal foam solution accumulator, the second pump 207 was set andstarted in a mode of pair constant pressure and the valves 211, 231 and235 to the external accumulator were opened, as shown in FIG. 2. Thethermal solution was routed via the valve 246, the automatic valve 249,the valve 250, to the automatic valve 252. When the pressure on bothsides of the automatic valve 252 was the same pressure, the second pump207 was stopped and restarted in a mode of pair constant flow rate toestablish an expectant injection flow rate of the thermal foam solution.The automatic valve 252 was opened, the automatic valve 254 to the highpermeable core plug in the first core holder 102 was opened, and theautomatic valve 255 to the low permeable core plug in the second coreholder 104 was closed. The thermal foam solution was routed through theimage capture system 112 via the valve 300, the viewing cell 308, andthe valve 316. The thermal foam solution was then routed from the imagecapture system 112 via the automatic valve 320 and through a bypass ofthe first core holder 102 via the valve 414 and the valve 454. Thethermal foam solution was then routed to the density and viscositymeasurement system 116 via the valve 460 and the automatic valve 466where the density and viscosity were measured. After evaluation andmeasurement of the thermal foam solution, the thermal foam solution wasinjected into the high permeable core plug in the first core holder 102by closing the bypass valves 412, 414, and 454 and routing the thermalfoam solution to the high permeable core plug via the inlet of the firstcore holder 102 via the valves 320 and 410 shown in FIG. 4A. The volumeof slug injection of the thermal foam solution as a percentage of porevolume of the high permeable core and the pressure build up duringinjection were recorded as a function of time.

The dual core flooding apparatus 100 may be used to perform post-CO2 orpost-seawater flooding on core plugs in the first core holder 102 andsecond core holder 104. A post-CO2 was conducted after the thermal foamsolution experiment. The external accumulator with the thermal foamsolution was replaced by accumulator 202 and the valves 302 and 318 ofthe image capture system 112 and the bypass valves 414 and 454 of thefirst core holder 102 were opened and the thermal foam solution wasflushed by routing CO2 to the first back pressure regulator 1000. Afterflushing the thermal foam solution, the valves 414 and 454 of the firstcore holder 102 were closed and the automatic valves 320 and 410 to thefirst core holder and the automatic valve 255 and the valve 416 to thesecond core holder 104 were opened. The post-CO2 injection procedure wasthe same as the initial CO2 injection procedure described supra, andboth the high permeable core plug in first core holder 102 and the lowpermeable core plug in the second core holder 104 were injected. Thepost-CO2 injection procedure was stopped when no more oil was producedfrom the high permeable core plug and the low permeable core plug. Thesecond pump 207 was stopped and the automatic valves 254 and 255 shownin FIG. 2 were closed. During the post-CO2 injection experiment, theamount of oil production from and the differential pressure across thehigh permeable core plug and the low permeable core plug were recordedas a function of time.

After the completion of the post-CO2 injection, the dual core floodingapparatus 100 was shut down by decreasing the temperature of the ovens132 and 134 to ambient temperature and removing the core plugs from thefirst core holder 102 and the second core holder 104. Before removingthe core plugs, all bypass valves for the image capture system 112, thecore holders 102 and 104, the density and viscosity measurement system116, and the oil/water separators 118 and 124 were opened. The porepressure was reduced by starting the first pump 206, the second pump 207or both in a pair constant pressure mode or by using the back pressureregulation systems 120 and 126. The confining pressure was reduced bysuing the automating confining pressure system 114. Both the porepressure and the confining pressure were reduced in 500 psi incrementsuntil zero pressure was achieved for the pore pressure and confiningpressure. Next, all inlet lines, outlet lines, bypass lines, and linesfor the differential pressure measurement systems 108 and 110 connectedto the core holders 102 and 104 were disconnected. The end caps of thecore holders 102 and 104 were removed and the fluid distribution plugsfor both ends in the core holders 102 and 104 were removed. The coreplugs were then taken out and a Dean Stark extraction was conducted todetermine residue oil saturation (S_(or)).

Ranges may be expressed in the disclosure as from about one particularvalue, to about another particular value, or both. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value, to the other particular value, or both, along withall combinations within said range.

Further modifications and alternative embodiments of various aspects ofthe disclosure will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the embodiments described inthe disclosure. It is to be understood that the forms shown anddescribed in the disclosure are to be taken as examples of embodiments.Elements and materials may be substituted for those illustrated anddescribed in the disclosure, parts and processes may be reversed oromitted, and certain features may be utilized independently, all aswould be apparent to one skilled in the art after having the benefit ofthis description. Changes may be made in the elements described in thedisclosure without departing from the spirit and scope of the disclosureas described in the following claims. Headings used in the disclosureare for organizational purposes only and are not meant to be used tolimit the scope of the description.

What is claimed is:
 1. A method for dual core flooding of a plurality ofcore plugs, comprising the steps of: introducing, by a fluids deliverysystem, at least one fluid into a first core holder and a second coreholder, the first core holder being operable to contain a first coreplug and the second core holder being operable to contain a second coreplug; separating, by a separator, hydrocarbon fluid from the at leastone fluid, the separator in fluid communication with an outlet port ofthe first core holder or an outlet port of the second core holder;maintaining, by a pressure confining system, a first confining pressurein the first core holder and a second confining pressure in the secondcore holder; maintaining, by a back pressure control system a first porepressure within the first core plug independent of a second porepressure associated with the second core plug; measuring, by a densitymeter coupled to the outlet port of the first core holder and the outletport of the second core holder, density of the at least one fluidexiting from the outlet port of the first core holder or the outlet portof the second core holder; measuring, by viscosity meter coupled to theoutlet port of the first core holder and the outlet port of the secondcore holder, a viscosity of the at least one fluid exiting from theoutlet port of the first core holder and the outlet port of the secondcore holder; and acquiring, by a data acquisition system, properties ofthe at least one fluid exiting from the outlet port of the first coreholder or the outlet port of the second core holder.
 2. The method ofclaim 1, wherein the at least one fluid comprises a first fluid and asecond fluid different than the first fluid, wherein introducing, by afluids delivery system, at least one fluid into a first core holder anda second core holder comprises: introducing the first fluid into thefirst core holder; and introducing the second fluid into the second coreholder.
 3. The method of claim 2, wherein the fluids delivery systemcomprises a plurality of valves, wherein introducing the first fluidinto the first core holder comprises opening a first group of theplurality of valves and closing a second group of the plurality ofvalves to define a first fluid flow path from a first fluid accumulatorof the fluids delivery system to the inlet port of the first core holderand a second fluid path from a second fluid accumulator of the fluidsdelivery system to the inlet port of the second core holder.
 4. Themethod of claim 2, wherein the at least one fluid comprises a thirdfluid, wherein introducing, by a fluids delivery system, at least onefluid into a first core holder and a second core holder comprises:introducing the third fluid into the first core holder after introducingthe first fluid into the first core holder.
 5. The method of claim 1,wherein the at least one fluid comprises a single fluid, whereinintroducing, by a fluids delivery system, at least one fluid into afirst core holder and a second core holder comprises introducing thesingle fluid into the first core holder and the second holder.
 6. Themethod of claim 5, wherein the fluids delivery system comprises aplurality of valves, wherein introducing the single fluid into the firstcore holder and the second core holder comprises opening a first groupof the plurality of valves and closing a second group of the pluralityof valves to define a first fluid flow path from a first fluidaccumulator of the fluids delivery system to the inlet port of the firstcore holder and a second fluid flow path from the first fluidaccumulator of the fluids delivery system to the inlet port of thesecond core holder.
 7. The method of claim 1, comprising introducing,via the fluids delivery system, a foam slug into the first core holder.8. The method of claim 1, wherein the at least one fluid comprises livecrude oil, dead crude oil, seawater or carbon dioxide.
 9. The method ofclaim 1, wherein the properties comprise at least one of a density, aviscosity, an amount of hydrocarbon fluid, and an amount of water.